@charset "UTF-8";
/* =============================================================
   DairyCalc.in — Main SCSS Entry Point
   ============================================================= */
/* ── Base ─────────────────────────────────────────────────── */
/* =============================================================
   DairyCalc Design System — CSS Custom Properties
   Industrial engineering platform color & spacing system
   ============================================================= */
:root {
  /* ── Brand Colors ─────────────────────────────────────────── */
  --color-primary:        #1e5fa8;
  --color-primary-hover:  #174d8a;
  --color-primary-light:  #e8f0fb;
  --color-primary-muted:  #5b8fcc;
  --color-secondary:      #4a5568;
  --color-secondary-hover:#374151;
  --color-accent:         #e07a2f;
  --color-accent-hover:   #c8691f;
  --color-accent-light:   #fef3e8;
  /* ── Semantic Colors ──────────────────────────────────────── */
  --color-success:        #2e7d52;
  --color-success-light:  #d1fadf;
  --color-success-text:   #166534;
  --color-warning:        #b45309;
  --color-warning-light:  #fef3c7;
  --color-warning-text:   #92400e;
  --color-danger:         #b91c1c;
  --color-danger-light:   #fee2e2;
  --color-danger-text:    #991b1b;
  --color-info:           #1d4ed8;
  --color-info-light:     #dbeafe;
  --color-info-text:      #1e40af;
  /* ── Light Mode Surfaces ──────────────────────────────────── */
  --color-bg:             #ffffff;
  --color-surface:        #f8fafc;
  --color-surface-2:      #f1f5f9;
  --color-card:           #ffffff;
  --color-border:         #e2e8f0;
  --color-border-2:       #cbd5e1;
  /* ── Light Mode Text ──────────────────────────────────────── */
  --color-text:           #1a202c;
  --color-text-muted:     #64748b;
  --color-text-subtle:    #94a3b8;
  --color-link:           #1e5fa8;
  --color-link-hover:     #174d8a;
  --color-link-visited:   #4338ca;
  /* ── Spacing Scale (8px base) ─────────────────────────────── */
  --space-1:   4px;
  --space-2:   8px;
  --space-3:   12px;
  --space-4:   16px;
  --space-5:   24px;
  --space-6:   32px;
  --space-7:   40px;
  --space-8:   48px;
  --space-9:   64px;
  --space-10:  80px;
  --space-11:  96px;
  --space-12:  128px;
  /* ── Layout ───────────────────────────────────────────────── */
  --container-sm:      720px;
  --container-md:      960px;
  --container-lg:      1200px;
  --container-xl:      1280px;
  --reading-width:     760px;
  --calculator-width:  900px;
  --sidebar-width:     300px;
  /* ── Border Radius ────────────────────────────────────────── */
  --radius-xs:   4px;
  --radius-sm:   6px;
  --radius-md:   10px;
  --radius-lg:   14px;
  --radius-xl:   20px;
  --radius-full: 9999px;
  /* ── Shadows ──────────────────────────────────────────────── */
  --shadow-xs:  0 1px 2px 0 rgba(0,0,0,0.05);
  --shadow-sm:  0 1px 3px 0 rgba(0,0,0,0.08), 0 1px 2px -1px rgba(0,0,0,0.06);
  --shadow-md:  0 4px 6px -1px rgba(0,0,0,0.08), 0 2px 4px -2px rgba(0,0,0,0.06);
  --shadow-lg:  0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.05);
  --shadow-xl:  0 20px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.04);
  /* ── Typography ───────────────────────────────────────────── */
  --font-sans:  Inter, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono:  "JetBrains Mono", Consolas, "Courier New", monospace;
  --text-xs:    0.75rem;
  /* 12px */
  --text-sm:    0.875rem;
  /* 14px */
  --text-base:  1rem;
  /* 16px */
  --text-lg:    1.125rem;
  /* 18px */
  --text-xl:    1.25rem;
  /* 20px */
  --text-2xl:   1.5rem;
  /* 24px */
  --text-3xl:   1.875rem;
  /* 30px */
  --text-4xl:   2.375rem;
  /* 38px */
  --text-5xl:   3rem;
  /* 48px */
  --weight-normal:    400;
  --weight-medium:    500;
  --weight-semibold:  600;
  --weight-bold:      700;
  --leading-tight:    1.25;
  --leading-snug:     1.4;
  --leading-normal:   1.6;
  --leading-relaxed:  1.7;
  --leading-loose:    1.8;
  /* ── Transitions ──────────────────────────────────────────── */
  --transition-fast:   150ms ease;
  --transition-base:   200ms ease;
  --transition-slow:   300ms ease;
  /* ── Z-index ──────────────────────────────────────────────── */
  --z-dropdown:  100;
  --z-sticky:    200;
  --z-modal:     300;
  --z-toast:     400;
  /* ── Navbar ───────────────────────────────────────────────── */
  --navbar-height:       64px;
  --navbar-bg:           rgba(255,255,255,0.95);
  --navbar-border:       var(--color-border);
  --navbar-blur:         saturate(180%) blur(12px); }

/* ── Dark Mode ─────────────────────────────────────────────── */
[data-theme="dark"] {
  --color-bg:            #0f1117;
  --color-surface:       #161b25;
  --color-surface-2:     #1e2736;
  --color-card:          #1a2130;
  --color-border:        #2d3748;
  --color-border-2:      #3d4a5c;
  --color-text:          #e2e8f0;
  --color-text-muted:    #94a3b8;
  --color-text-subtle:   #64748b;
  --color-link:          #63a0e8;
  --color-link-hover:    #89bef5;
  --color-link-visited:  #a78bfa;
  --color-primary:       #4a90d9;
  --color-primary-hover: #63a0e8;
  --color-primary-light: #1a2a42;
  --color-primary-muted: #5b8fcc;
  --color-accent:        #f59c4a;
  --color-accent-hover:  #f7b06d;
  --color-accent-light:  #2a1f10;
  --color-success-light: #0d2b1a;
  --color-warning-light: #2b1f0a;
  --color-danger-light:  #2b0f0f;
  --color-info-light:    #0d1a2b;
  --shadow-xs:  0 1px 2px 0 rgba(0,0,0,0.3);
  --shadow-sm:  0 1px 3px 0 rgba(0,0,0,0.35), 0 1px 2px -1px rgba(0,0,0,0.3);
  --shadow-md:  0 4px 6px -1px rgba(0,0,0,0.35), 0 2px 4px -2px rgba(0,0,0,0.3);
  --shadow-lg:  0 10px 15px -3px rgba(0,0,0,0.4), 0 4px 6px -4px rgba(0,0,0,0.25);
  --navbar-bg:     rgba(15,17,23,0.95);
  --navbar-border: var(--color-border); }

/* =============================================================
   DairyCalc — Reset & Base Styles
   ============================================================= */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0; }

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%; }

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--weight-normal);
  line-height: var(--leading-relaxed);
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color var(--transition-slow), color var(--transition-slow);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale; }

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-4);
  z-index: 9999;
  padding: var(--space-2) var(--space-4);
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-md);
  font-weight: var(--weight-semibold);
  text-decoration: none;
  transition: top var(--transition-fast); }

.skip-link:focus {
  top: var(--space-4); }

/* Focus visible */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-xs); }

/* Selection */
::selection {
  background: var(--color-primary-light);
  color: var(--color-primary); }

/* Links */
a {
  color: var(--color-link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color var(--transition-fast); }

a:hover {
  color: var(--color-link-hover); }

a:visited {
  color: var(--color-link-visited); }

/* Images */
img, video, svg {
  display: block;
  max-width: 100%;
  height: auto; }

/* Lists */
ul, ol {
  list-style: none; }

/* HR */
hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-8) 0; }

/* Code */
code, kbd, samp {
  font-family: var(--font-mono);
  font-size: 0.875em; }

/* Pre */
pre {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  overflow-x: auto;
  line-height: 1.6; }

pre code {
  font-size: inherit;
  background: none;
  border: none;
  padding: 0; }

/* Inline code */
:not(pre) > code {
  background: var(--color-surface-2);
  color: var(--color-accent);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xs);
  padding: 0.1em 0.4em;
  font-size: 0.875em; }

/* Table */
table {
  width: 100%;
  border-collapse: collapse; }

/* Blockquote */
blockquote {
  border-left: 4px solid var(--color-primary);
  padding: var(--space-4) var(--space-5);
  background: var(--color-primary-light);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  color: var(--color-text);
  font-style: italic; }

/* Strong */
strong {
  font-weight: var(--weight-semibold); }

/* Small */
small {
  font-size: var(--text-sm); }

/* Mark */
mark {
  background: var(--color-warning-light);
  color: var(--color-warning-text);
  border-radius: var(--radius-xs);
  padding: 0.1em 0.3em; }

/* =============================================================
   DairyCalc — Typography System
   Optimized for long technical reading
   ============================================================= */
/* Headings */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: var(--weight-bold);
  line-height: var(--leading-tight);
  color: var(--color-text);
  letter-spacing: -0.02em; }

h1 {
  font-size: var(--text-5xl); }

h2 {
  font-size: var(--text-4xl); }

h3 {
  font-size: var(--text-3xl); }

h4 {
  font-size: var(--text-2xl); }

h5 {
  font-size: var(--text-xl); }

h6 {
  font-size: var(--text-lg); }

@media (max-width: 768px) {
  h1 {
    font-size: 2.25rem; }
  h2 {
    font-size: 1.875rem; }
  h3 {
    font-size: 1.5rem; }
  h4 {
    font-size: 1.25rem; } }

/* Body text sizes */
.text-xs {
  font-size: var(--text-xs); }

.text-sm {
  font-size: var(--text-sm); }

.text-base {
  font-size: var(--text-base); }

.text-lg {
  font-size: var(--text-lg); }

.text-xl {
  font-size: var(--text-xl); }

.text-2xl {
  font-size: var(--text-2xl); }

.text-3xl {
  font-size: var(--text-3xl); }

.text-4xl {
  font-size: var(--text-4xl); }

.text-5xl {
  font-size: var(--text-5xl); }

/* Font weights */
.font-normal {
  font-weight: var(--weight-normal); }

.font-medium {
  font-weight: var(--weight-medium); }

.font-semibold {
  font-weight: var(--weight-semibold); }

.font-bold {
  font-weight: var(--weight-bold); }

/* Text colors */
.text-primary {
  color: var(--color-primary); }

.text-muted {
  color: var(--color-text-muted); }

.text-subtle {
  color: var(--color-text-subtle); }

.text-success {
  color: var(--color-success); }

.text-warning {
  color: var(--color-warning); }

.text-danger {
  color: var(--color-danger); }

.text-accent {
  color: var(--color-accent); }

/* Alignment */
.text-left {
  text-align: left; }

.text-center {
  text-align: center; }

.text-right {
  text-align: right; }

/* Lead paragraph */
.lead {
  font-size: var(--text-lg);
  font-weight: var(--weight-normal);
  color: var(--color-text-muted);
  line-height: var(--leading-relaxed); }

/* Prose — long-form reading content */
.prose {
  max-width: var(--reading-width);
  color: var(--color-text);
  line-height: var(--leading-relaxed); }

.prose h2 {
  font-size: var(--text-3xl);
  margin-top: var(--space-9);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  border-bottom: 2px solid var(--color-border); }

.prose h3 {
  font-size: var(--text-2xl);
  margin-top: var(--space-8);
  margin-bottom: var(--space-3); }

.prose h4 {
  font-size: var(--text-xl);
  margin-top: var(--space-6);
  margin-bottom: var(--space-3); }

.prose p {
  margin-bottom: var(--space-5);
  line-height: var(--leading-relaxed); }

.prose ul, .prose ol {
  margin-bottom: var(--space-5);
  padding-left: var(--space-6); }

.prose ul {
  list-style: disc; }

.prose ol {
  list-style: decimal; }

.prose li {
  margin-bottom: var(--space-2);
  line-height: var(--leading-relaxed); }

.prose a {
  color: var(--color-link);
  text-decoration: underline;
  text-decoration-thickness: 1px; }

.prose a:hover {
  color: var(--color-link-hover); }

.prose strong {
  font-weight: var(--weight-semibold);
  color: var(--color-text); }

.prose table {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: var(--space-6);
  font-size: var(--text-sm); }

.prose th {
  background: var(--color-surface);
  font-weight: var(--weight-semibold);
  text-align: left;
  padding: var(--space-3) var(--space-4);
  border-bottom: 2px solid var(--color-border);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted); }

.prose td {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  vertical-align: top; }

.prose tr:last-child td {
  border-bottom: none; }

.prose tr:hover td {
  background: var(--color-surface); }

/* Formula display */
.formula {
  font-family: var(--font-mono);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-md);
  padding: var(--space-5) var(--space-6);
  font-size: var(--text-lg);
  overflow-x: auto;
  margin: var(--space-6) 0;
  color: var(--color-text); }

/* Category label */
.category-label {
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted); }

/* ── Layout ───────────────────────────────────────────────── */
/* =============================================================
   DairyCalc — Layout Components
   Grid, containers, page layouts
   ============================================================= */
/* Container */
.container {
  width: 100%;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--space-5); }

.container--sm {
  max-width: var(--container-sm); }

.container--md {
  max-width: var(--container-md); }

.container--lg {
  max-width: var(--container-lg); }

.container--reading {
  max-width: var(--reading-width); }

/* Section spacing */
.section {
  padding: var(--space-11) 0; }

.section--sm {
  padding: var(--space-8) 0; }

.section--lg {
  padding: var(--space-12) 0; }

/* Section header */
.section-header {
  text-align: center;
  margin-bottom: var(--space-9); }

.section-header__eyebrow {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-primary);
  margin-bottom: var(--space-3); }

.section-header__title {
  font-size: var(--text-4xl);
  font-weight: var(--weight-bold);
  color: var(--color-text);
  letter-spacing: -0.02em;
  margin-bottom: var(--space-4); }

.section-header__desc {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: 560px;
  margin: 0 auto;
  line-height: var(--leading-relaxed); }

.section-header--left {
  text-align: left; }

.section-header--left .section-header__desc {
  margin: 0; }

/* Section footer (view all link) */
.section-footer {
  text-align: center;
  margin-top: var(--space-8); }

/* Grid layouts */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-5); }

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5); }

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-5); }

.grid-auto {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-5); }

.grid-auto--sm {
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }

.grid-auto--lg {
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); }

@media (max-width: 1024px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr); } }

@media (max-width: 768px) {
  .grid-3 {
    grid-template-columns: repeat(2, 1fr); } }

@media (max-width: 640px) {
  .grid-2 {
    grid-template-columns: 1fr; }
  .grid-3 {
    grid-template-columns: 1fr; }
  .grid-4 {
    grid-template-columns: repeat(2, 1fr); } }

@media (max-width: 480px) {
  .grid-4 {
    grid-template-columns: 1fr; } }

/* Main content with sidebar */
.content-with-sidebar {
  display: grid;
  grid-template-columns: 1fr var(--sidebar-width);
  gap: var(--space-9);
  align-items: start; }

@media (max-width: 1024px) {
  .content-with-sidebar {
    grid-template-columns: 1fr; }
  .sidebar {
    display: none; } }

/* Sidebar */
.sidebar {
  position: sticky;
  top: calc(var(--navbar-height) + var(--space-5));
  display: flex;
  flex-direction: column;
  gap: var(--space-5); }

.sidebar-widget {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden; }

.sidebar-widget__title {
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--color-text-muted);
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface); }

.sidebar-widget__body {
  padding: var(--space-4); }

.sidebar-calc-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-1); }

.sidebar-calc-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  transition: all var(--transition-fast); }

.sidebar-calc-item:hover {
  background: var(--color-surface);
  color: var(--color-primary);
  text-decoration: none; }

/* Footer */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--space-11) 0 var(--space-6);
  margin-top: var(--space-12); }

.footer__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-8);
  margin-bottom: var(--space-9); }

@media (max-width: 900px) {
  .footer__grid {
    grid-template-columns: repeat(2, 1fr); } }

@media (max-width: 480px) {
  .footer__grid {
    grid-template-columns: 1fr; } }

.footer__col-title {
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--color-text);
  margin-bottom: var(--space-4); }

.footer__col-brand {
  display: flex;
  flex-direction: column;
  gap: var(--space-3); }

.footer__brand-desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: var(--leading-relaxed); }

.footer__nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-2); }

.footer__nav-link {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition-fast); }

.footer__nav-link:hover {
  color: var(--color-primary);
  text-decoration: none; }

.footer__bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
  flex-wrap: wrap; }

.footer__copyright {
  font-size: var(--text-sm);
  color: var(--color-text-muted); }

.footer__social {
  display: flex;
  align-items: center;
  gap: var(--space-3); }

.footer__social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: all var(--transition-fast); }

.footer__social-link:hover {
  background: var(--color-primary-light);
  border-color: var(--color-primary);
  color: var(--color-primary);
  text-decoration: none; }

/* Main page content area */
.page-main {
  padding: var(--space-8) 0 var(--space-11); }

/* Divider */
.divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-8) 0; }

/* Page title area */
.page-header {
  padding: var(--space-8) 0 var(--space-6);
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--space-8); }

.page-header__breadcrumb {
  margin-bottom: var(--space-3); }

.page-header__category {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--color-primary);
  margin-bottom: var(--space-3); }

.page-header__title {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: var(--weight-bold);
  color: var(--color-text);
  line-height: var(--leading-tight);
  letter-spacing: -0.02em;
  margin-bottom: var(--space-4); }

.page-header__desc {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: var(--reading-width);
  line-height: var(--leading-relaxed); }

/* Pagination */
.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-8) 0; }

.pagination__btn {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 36px;
  height: 36px;
  padding: 0 var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  text-decoration: none;
  transition: all var(--transition-fast);
  font-family: var(--font-sans);
  cursor: pointer; }

.pagination__btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-light);
  text-decoration: none; }

.pagination__btn.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff; }

.pagination__btn:disabled {
  opacity: 0.4;
  cursor: not-allowed; }

/* Share component */
.share-bar {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap; }

.share-bar__label {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--color-text-muted); }

.share-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 6px var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  color: var(--color-text-muted);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  cursor: pointer;
  font-family: var(--font-sans);
  text-decoration: none;
  transition: all var(--transition-fast); }

.share-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-light);
  text-decoration: none; }

/* ── Components ───────────────────────────────────────────── */
/* =============================================================
   DairyCalc — Navbar Component
   Sticky, blur, responsive with mobile drawer
   ============================================================= */
.navbar {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  height: var(--navbar-height);
  background: var(--navbar-bg);
  border-bottom: 1px solid var(--navbar-border);
  backdrop-filter: var(--navbar-blur);
  -webkit-backdrop-filter: var(--navbar-blur);
  transition: box-shadow var(--transition-base); }

.navbar.scrolled {
  box-shadow: var(--shadow-sm); }

.navbar__inner {
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--space-5);
  height: 100%;
  display: flex;
  align-items: center;
  gap: var(--space-6); }

/* Logo */
.navbar__logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-text);
  font-weight: var(--weight-bold);
  font-size: var(--text-xl);
  letter-spacing: -0.03em;
  flex-shrink: 0; }

.navbar__logo-mark {
  width: 36px;
  height: 36px;
  background: var(--color-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: var(--text-lg);
  font-weight: var(--weight-bold);
  letter-spacing: -0.05em; }

.navbar__logo-text span {
  color: var(--color-primary); }

.navbar__logo:hover {
  color: var(--color-text);
  text-decoration: none; }

/* Nav menu */
.navbar__nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex: 1; }

.navbar__nav-link {
  display: flex;
  align-items: center;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: background-color var(--transition-fast), color var(--transition-fast);
  white-space: nowrap; }

.navbar__nav-link:hover {
  background: var(--color-surface);
  color: var(--color-text);
  text-decoration: none; }

.navbar__nav-link.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
  font-weight: var(--weight-semibold); }

/* Navbar actions */
.navbar__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto; }

.navbar__icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast), color var(--transition-fast); }

.navbar__icon-btn:hover {
  background: var(--color-surface);
  color: var(--color-text); }

/* Search trigger button */
.navbar__search-btn {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: var(--text-sm);
  font-family: var(--font-sans);
  transition: all var(--transition-fast);
  min-width: 160px;
  text-align: left; }

.navbar__search-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-text);
  background: var(--color-bg); }

.navbar__search-kbd {
  margin-left: auto;
  font-size: var(--text-xs);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 1px 5px;
  color: var(--color-text-subtle);
  font-family: var(--font-mono); }

/* Mobile hamburger */
.navbar__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 6px;
  border-radius: var(--radius-md);
  transition: background-color var(--transition-fast); }

.navbar__hamburger:hover {
  background: var(--color-surface); }

.navbar__hamburger-line {
  width: 100%;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-base); }

.navbar__hamburger[aria-expanded="true"] .navbar__hamburger-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg); }

.navbar__hamburger[aria-expanded="true"] .navbar__hamburger-line:nth-child(2) {
  opacity: 0; }

.navbar__hamburger[aria-expanded="true"] .navbar__hamburger-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg); }

/* Mobile drawer overlay */
.mobile-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 199;
  opacity: 0;
  transition: opacity var(--transition-base); }

.mobile-overlay.open {
  display: block;
  opacity: 1; }

/* Mobile drawer */
.mobile-drawer {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: MIN(320px, 90vw);
  z-index: 200;
  background: var(--color-bg);
  box-shadow: var(--shadow-xl);
  transform: translateX(100%);
  transition: transform var(--transition-slow);
  overflow-y: auto;
  display: flex;
  flex-direction: column; }

.mobile-drawer.open {
  transform: translateX(0); }

.mobile-drawer__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--color-border);
  height: var(--navbar-height); }

.mobile-drawer__nav {
  flex: 1;
  padding: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-1); }

.mobile-drawer__nav-link {
  display: flex;
  align-items: center;
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  font-weight: var(--weight-medium);
  color: var(--color-text);
  text-decoration: none;
  transition: background-color var(--transition-fast); }

.mobile-drawer__nav-link:hover {
  background: var(--color-surface);
  text-decoration: none;
  color: var(--color-text); }

.mobile-drawer__nav-link.active {
  background: var(--color-primary-light);
  color: var(--color-primary); }

.mobile-drawer__footer {
  padding: var(--space-4) var(--space-5);
  border-top: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  gap: var(--space-3); }

/* Responsive */
@media (max-width: 900px) {
  .navbar__nav {
    display: none; }
  .navbar__search-btn {
    display: none; }
  .navbar__hamburger {
    display: flex; } }

@media (max-width: 480px) {
  .navbar__logo-text {
    display: none; } }

/* =============================================================
   DairyCalc — Button Components
   ============================================================= */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 10px var(--space-5);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  line-height: 1;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  transition: background-color var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
  user-select: none;
  -webkit-user-select: none;
  appearance: none; }

.btn:hover {
  text-decoration: none;
  transform: translateY(-1px); }

.btn:active {
  transform: translateY(0); }

.btn:disabled, .btn[aria-disabled="true"] {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none; }

/* Sizes */
.btn--sm {
  padding: 7px var(--space-4);
  font-size: var(--text-xs); }

.btn--lg {
  padding: 14px var(--space-7);
  font-size: var(--text-base); }

.btn--xl {
  padding: 16px var(--space-8);
  font-size: var(--text-lg); }

/* Variants */
.btn--primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
  box-shadow: 0 1px 2px rgba(30, 95, 168, 0.3); }

.btn--primary:hover {
  background: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  box-shadow: 0 3px 8px rgba(30, 95, 168, 0.4);
  color: #fff; }

.btn--secondary {
  background: var(--color-surface);
  color: var(--color-text);
  border-color: var(--color-border); }

.btn--secondary:hover {
  background: var(--color-surface-2);
  border-color: var(--color-border-2);
  color: var(--color-text); }

.btn--outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary); }

.btn--outline:hover {
  background: var(--color-primary-light);
  color: var(--color-primary); }

.btn--ghost {
  background: transparent;
  color: var(--color-text-muted);
  border-color: transparent; }

.btn--ghost:hover {
  background: var(--color-surface);
  color: var(--color-text); }

.btn--accent {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent); }

.btn--accent:hover {
  background: var(--color-accent-hover);
  border-color: var(--color-accent-hover);
  color: #fff; }

.btn--danger {
  background: var(--color-danger);
  color: #fff;
  border-color: var(--color-danger); }

.btn--danger:hover {
  background: #9b1515;
  color: #fff; }

.btn--success {
  background: var(--color-success);
  color: #fff;
  border-color: var(--color-success); }

.btn--success:hover {
  background: #236040;
  color: #fff; }

/* Icon button */
.btn--icon {
  padding: var(--space-2);
  width: 36px;
  height: 36px; }

.btn--icon.btn--sm {
  width: 28px;
  height: 28px;
  padding: var(--space-1); }

/* Full width */
.btn--full {
  width: 100%; }

/* Loading state */
.btn--loading {
  position: relative;
  color: transparent;
  cursor: wait;
  pointer-events: none; }

.btn--loading::after {
  content: '';
  position: absolute;
  width: 16px;
  height: 16px;
  border: 2px solid rgba(255, 255, 255, 0.4);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.6s linear infinite; }

@keyframes spin {
  to {
    transform: rotate(360deg); } }

/* =============================================================
   DairyCalc — Card Components
   ============================================================= */
/* Base card */
.card {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  box-shadow: var(--shadow-xs);
  transition: box-shadow var(--transition-base), border-color var(--transition-base), transform var(--transition-base); }

.card--hoverable:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
  transform: translateY(-2px); }

.card--flat {
  box-shadow: none;
  border-color: var(--color-border); }

.card--surface {
  background: var(--color-surface); }

/* ── Calculator Card ──────────────────────────────────────── */
.calc-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  box-shadow: var(--shadow-xs);
  text-decoration: none;
  color: var(--color-text);
  transition: box-shadow var(--transition-base), border-color var(--transition-base), transform var(--transition-base);
  position: relative;
  overflow: hidden; }

.calc-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--color-primary);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base); }

.calc-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
  transform: translateY(-2px);
  text-decoration: none;
  color: var(--color-text); }

.calc-card:hover::after {
  transform: scaleX(1); }

.calc-card__header {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3); }

.calc-card__icon {
  width: 44px;
  height: 44px;
  background: var(--color-primary-light);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  flex-shrink: 0;
  transition: background-color var(--transition-base); }

.calc-card:hover .calc-card__icon {
  background: var(--color-primary);
  color: #fff; }

.calc-card__meta {
  flex: 1;
  min-width: 0; }

.calc-card__category {
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-1); }

.calc-card__title {
  font-size: var(--text-base);
  font-weight: var(--weight-semibold);
  color: var(--color-text);
  line-height: 1.4;
  margin: 0; }

.calc-card__desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.5;
  margin: 0;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden; }

.calc-card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-top: auto; }

/* ── Category Card ────────────────────────────────────────── */
.cat-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-3);
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  text-decoration: none;
  color: var(--color-text);
  transition: box-shadow var(--transition-base), border-color var(--transition-base), transform var(--transition-base), background-color var(--transition-base); }

.cat-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
  transform: translateY(-2px);
  background: var(--color-primary-light);
  text-decoration: none;
  color: var(--color-text); }

.cat-card__icon {
  width: 48px;
  height: 48px;
  background: var(--color-surface);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  transition: all var(--transition-base); }

.cat-card:hover .cat-card__icon {
  background: var(--color-primary);
  color: #fff; }

.cat-card__title {
  font-size: var(--text-base);
  font-weight: var(--weight-semibold);
  margin: 0; }

.cat-card__desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.5;
  margin: 0;
  flex: 1; }

.cat-card__count {
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  color: var(--color-text-subtle);
  padding: 2px 8px;
  background: var(--color-surface-2);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border); }

/* ── Article Card ─────────────────────────────────────────── */
.article-card {
  display: flex;
  flex-direction: column;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  text-decoration: none;
  color: var(--color-text);
  transition: box-shadow var(--transition-base), transform var(--transition-base); }

.article-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  text-decoration: none;
  color: var(--color-text); }

.article-card__image {
  aspect-ratio: 16/9;
  overflow: hidden;
  background: var(--color-surface); }

.article-card__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow); }

.article-card:hover .article-card__image img {
  transform: scale(1.03); }

.article-card__body {
  padding: var(--space-5);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  flex: 1; }

.article-card__category {
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-primary); }

.article-card__title {
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
  line-height: 1.4;
  margin: 0;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden; }

.article-card__summary {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin: 0;
  flex: 1; }

.article-card__footer {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding-top: var(--space-3);
  border-top: 1px solid var(--color-border);
  font-size: var(--text-xs);
  color: var(--color-text-subtle); }

/* ── Result Card (calculator output) ─────────────────────── */
.result-card {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-hover) 100%);
  color: #fff;
  border-radius: var(--radius-lg);
  padding: var(--space-7) var(--space-6);
  text-align: center;
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden; }

.result-card::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.08) 0%, transparent 60%);
  pointer-events: none; }

.result-card__label {
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  opacity: 0.85;
  margin-bottom: var(--space-2);
  text-transform: uppercase;
  letter-spacing: 0.06em; }

.result-card__value {
  font-size: 3.5rem;
  font-weight: var(--weight-bold);
  line-height: 1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-2); }

.result-card__unit {
  font-size: var(--text-xl);
  font-weight: var(--weight-medium);
  opacity: 0.9;
  margin-bottom: var(--space-5); }

.result-card__actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  flex-wrap: wrap; }

.result-card__btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 7px var(--space-4);
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.3);
  color: #fff;
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  cursor: pointer;
  font-family: var(--font-sans);
  transition: background-color var(--transition-fast); }

.result-card__btn:hover {
  background: rgba(255, 255, 255, 0.25); }

/* Multiple outputs */
.result-card--multi {
  background: var(--color-card);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm); }

.result-card--multi::before {
  display: none; }

.result-outputs {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: var(--space-4); }

.result-output {
  background: var(--color-surface);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  text-align: center;
  border: 1px solid var(--color-border); }

.result-output__value {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  color: var(--color-primary);
  line-height: 1;
  letter-spacing: -0.02em; }

.result-output__unit {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin: var(--space-1) 0; }

.result-output__label {
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-subtle); }

/* =============================================================
   DairyCalc — Form Components
   ============================================================= */
/* Form group */
.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2); }

/* Label */
.form-label {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--color-text);
  display: flex;
  align-items: center;
  gap: var(--space-2); }

.form-label .required {
  color: var(--color-danger);
  font-size: var(--text-sm); }

/* Input base */
.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 10px var(--space-4);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  color: var(--color-text);
  background: var(--color-bg);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-fast);
  appearance: none;
  -webkit-appearance: none; }

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--color-text-subtle); }

.form-input:hover,
.form-select:hover,
.form-textarea:hover {
  border-color: var(--color-border-2); }

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(30, 95, 168, 0.12);
  background: var(--color-bg); }

/* Input with unit suffix */
.form-input-wrapper {
  position: relative;
  display: flex;
  align-items: stretch; }

.form-input-wrapper .form-input {
  border-radius: var(--radius-md) 0 0 var(--radius-md);
  flex: 1; }

.form-input-suffix {
  display: flex;
  align-items: center;
  padding: 0 var(--space-3);
  background: var(--color-surface);
  border: 1.5px solid var(--color-border);
  border-left: none;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: var(--weight-medium);
  white-space: nowrap;
  min-width: 44px;
  justify-content: center; }

/* Select */
.form-select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: var(--space-8);
  cursor: pointer; }

/* Textarea */
.form-textarea {
  min-height: 100px;
  resize: vertical;
  line-height: var(--leading-relaxed); }

/* States */
.form-input.is-error,
.form-select.is-error {
  border-color: var(--color-danger); }

.form-input.is-error:focus,
.form-select.is-error:focus {
  box-shadow: 0 0 0 3px rgba(185, 28, 28, 0.12); }

.form-input.is-success {
  border-color: var(--color-success); }

/* Help text */
.form-help {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  line-height: 1.5; }

/* Error message */
.form-error {
  font-size: var(--text-xs);
  color: var(--color-danger);
  font-weight: var(--weight-medium);
  display: flex;
  align-items: center;
  gap: var(--space-1); }

/* Calculator form layout */
.calc-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-5); }

.calc-form__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-5); }

.calc-form__actions {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap; }

/* Range input */
.form-range {
  width: 100%;
  height: 6px;
  appearance: none;
  -webkit-appearance: none;
  background: var(--color-border);
  border-radius: var(--radius-full);
  outline: none;
  cursor: pointer; }

.form-range::-webkit-slider-thumb {
  appearance: none;
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 2px solid #fff;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: box-shadow var(--transition-fast); }

.form-range::-webkit-slider-thumb:hover {
  box-shadow: 0 0 0 4px var(--color-primary-light); }

/* Checkbox & Radio */
.form-check {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  cursor: pointer; }

.form-check__input {
  width: 18px;
  height: 18px;
  margin-top: 2px;
  flex-shrink: 0;
  appearance: none;
  -webkit-appearance: none;
  border: 2px solid var(--color-border-2);
  border-radius: var(--radius-xs);
  background: var(--color-bg);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative; }

.form-check__input[type="radio"] {
  border-radius: 50%; }

.form-check__input:checked {
  background: var(--color-primary);
  border-color: var(--color-primary); }

.form-check__input:checked::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 6px;
  height: 6px;
  background: #fff;
  border-radius: 1px; }

.form-check__input[type="radio"]:checked::after {
  border-radius: 50%; }

.form-check__label {
  font-size: var(--text-sm);
  color: var(--color-text);
  line-height: 1.5;
  user-select: none; }

/* =============================================================
   DairyCalc — Hero Section
   Compact, above-the-fold, no giant image
   ============================================================= */
.hero {
  background: var(--color-bg);
  padding: var(--space-11) 0 var(--space-9);
  position: relative;
  overflow: hidden; }

/* Subtle grid background pattern */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: linear-gradient(var(--color-border) 1px, transparent 1px), linear-gradient(90deg, var(--color-border) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: 0.3;
  pointer-events: none; }

/* Gradient fade at bottom */
.hero::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 120px;
  background: linear-gradient(to bottom, transparent, var(--color-bg));
  pointer-events: none; }

.hero__inner {
  position: relative;
  z-index: 1;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--space-5);
  text-align: center; }

/* Eyebrow badge */
.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 5px var(--space-4);
  background: var(--color-primary-light);
  border: 1px solid rgba(30, 95, 168, 0.2);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-5); }

/* Headline */
.hero__headline {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: var(--weight-bold);
  line-height: var(--leading-tight);
  color: var(--color-text);
  letter-spacing: -0.03em;
  margin-bottom: var(--space-5);
  max-width: 800px;
  margin-left: auto;
  margin-right: auto; }

.hero__headline em {
  font-style: normal;
  color: var(--color-primary); }

/* Subheading */
.hero__sub {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-8);
  max-width: 580px;
  margin-left: auto;
  margin-right: auto; }

/* Search bar */
.hero__search {
  max-width: 600px;
  margin: 0 auto var(--space-7);
  position: relative; }

.hero__search-form {
  display: flex;
  gap: 0;
  box-shadow: var(--shadow-lg);
  border-radius: var(--radius-xl);
  overflow: hidden;
  border: 2px solid var(--color-border);
  background: var(--color-bg);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast); }

.hero__search-form:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 4px rgba(30, 95, 168, 0.12), var(--shadow-lg); }

.hero__search-icon {
  display: flex;
  align-items: center;
  padding: 0 var(--space-4);
  color: var(--color-text-subtle); }

.hero__search-input {
  flex: 1;
  border: none;
  outline: none;
  font-family: var(--font-sans);
  font-size: var(--text-base);
  color: var(--color-text);
  background: transparent;
  padding: 14px var(--space-3); }

.hero__search-input::placeholder {
  color: var(--color-text-subtle); }

.hero__search-submit {
  padding: var(--space-3) var(--space-5);
  background: var(--color-primary);
  color: #fff;
  border: none;
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  cursor: pointer;
  transition: background-color var(--transition-fast);
  white-space: nowrap; }

.hero__search-submit:hover {
  background: var(--color-primary-hover); }

/* Popular searches */
.hero__popular {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  flex-wrap: wrap;
  font-size: var(--text-sm);
  color: var(--color-text-muted); }

.hero__popular-label {
  font-weight: var(--weight-medium);
  color: var(--color-text-subtle); }

.hero__popular-tag {
  display: inline-flex;
  align-items: center;
  padding: 3px var(--space-3);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: all var(--transition-fast); }

.hero__popular-tag:hover {
  background: var(--color-primary-light);
  border-color: var(--color-primary);
  color: var(--color-primary);
  text-decoration: none; }

/* Stats bar */
.hero__stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-8);
  flex-wrap: wrap;
  margin-top: var(--space-8);
  padding-top: var(--space-7);
  border-top: 1px solid var(--color-border); }

.hero__stat {
  text-align: center; }

.hero__stat-value {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  color: var(--color-primary);
  line-height: 1;
  letter-spacing: -0.03em; }

.hero__stat-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: var(--weight-medium);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-top: var(--space-1); }

/* =============================================================
   DairyCalc — Calculator Page Component
   ============================================================= */
.calculator-page {
  max-width: var(--calculator-width);
  margin: 0 auto; }

/* Calculator widget container */
.calculator-widget {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  margin-bottom: var(--space-8); }

.calculator-widget__header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-5) var(--space-6);
  display: flex;
  align-items: center;
  gap: var(--space-4); }

.calculator-widget__icon {
  width: 48px;
  height: 48px;
  background: var(--color-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  flex-shrink: 0; }

.calculator-widget__title {
  font-size: var(--text-xl);
  font-weight: var(--weight-bold);
  color: var(--color-text);
  margin: 0; }

.calculator-widget__desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin: 0;
  margin-top: var(--space-1); }

.calculator-widget__body {
  padding: var(--space-6); }

/* Input grid */
.calculator-inputs {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-5);
  margin-bottom: var(--space-6); }

/* Actions row */
.calculator-actions {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
  padding-top: var(--space-5);
  border-top: 1px solid var(--color-border);
  margin-top: var(--space-5); }

/* Result area */
.calculator-result {
  padding: var(--space-6);
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
  display: none;
  flex-direction: column;
  gap: var(--space-5); }

.calculator-result.visible {
  display: flex; }

/* Formula block */
.formula-block {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-md);
  padding: var(--space-5) var(--space-6);
  margin: var(--space-6) 0; }

.formula-block__title {
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--color-primary);
  margin-bottom: var(--space-3); }

.formula-block__expression {
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  color: var(--color-text);
  line-height: 1.6;
  overflow-x: auto; }

.formula-block__vars {
  margin-top: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-2); }

.formula-block__var {
  display: flex;
  gap: var(--space-3);
  font-size: var(--text-sm); }

.formula-block__var-name {
  font-family: var(--font-mono);
  color: var(--color-primary);
  font-weight: var(--weight-semibold);
  min-width: 60px; }

.formula-block__var-desc {
  color: var(--color-text-muted); }

/* Worked example */
.example-block {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin: var(--space-6) 0; }

.example-block__header {
  background: var(--color-accent-light);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-3) var(--space-5);
  display: flex;
  align-items: center;
  gap: var(--space-2); }

.example-block__title {
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.06em; }

.example-block__body {
  padding: var(--space-5); }

.example-block__step {
  display: flex;
  gap: var(--space-4);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border); }

.example-block__step:last-child {
  border-bottom: none; }

.example-block__step-num {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: 2px; }

.example-block__step-content {
  font-size: var(--text-sm);
  color: var(--color-text);
  line-height: 1.6; }

.example-block__step-formula {
  font-family: var(--font-mono);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--space-2) var(--space-3);
  margin-top: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-primary); }

/* Validation messages */
.field-error {
  display: none;
  font-size: var(--text-xs);
  color: var(--color-danger);
  font-weight: var(--weight-medium);
  margin-top: var(--space-1); }

.field-error.visible {
  display: block; }

/* Copy feedback */
.copy-success {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-xs);
  color: var(--color-success);
  animation: fadeOut 2s ease forwards; }

@keyframes fadeOut {
  0% {
    opacity: 1; }
  70% {
    opacity: 1; }
  100% {
    opacity: 0; } }

/* =============================================================
   DairyCalc — FAQ Accordion Component
   ============================================================= */
.faq-section {
  margin: var(--space-9) 0; }

.faq-section__title {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  margin-bottom: var(--space-6);
  color: var(--color-text); }

.faq-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2); }

/* Accordion item */
.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-card);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast); }

.faq-item.open {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 2px rgba(30, 95, 168, 0.08); }

/* Question button */
.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-5) var(--space-5);
  background: transparent;
  border: none;
  text-align: left;
  cursor: pointer;
  font-family: var(--font-sans);
  transition: background-color var(--transition-fast); }

.faq-question:hover {
  background: var(--color-surface); }

.faq-question__text {
  font-size: var(--text-base);
  font-weight: var(--weight-semibold);
  color: var(--color-text);
  line-height: 1.5; }

.faq-question__icon {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
  color: var(--color-text-muted);
  transition: transform var(--transition-base), color var(--transition-fast); }

.faq-item.open .faq-question__icon {
  transform: rotate(180deg);
  color: var(--color-primary); }

/* Answer */
.faq-answer {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--transition-base); }

.faq-item.open .faq-answer {
  grid-template-rows: 1fr; }

.faq-answer__inner {
  overflow: hidden; }

.faq-answer__content {
  padding: 0 var(--space-5) var(--space-5);
  font-size: var(--text-base);
  color: var(--color-text-muted);
  line-height: var(--leading-relaxed);
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-4); }

.faq-answer__content p {
  margin-bottom: var(--space-3); }

.faq-answer__content p:last-child {
  margin-bottom: 0; }

.faq-answer__content a {
  color: var(--color-link); }

/* =============================================================
   DairyCalc — Newsletter Component
   ============================================================= */
.newsletter-section {
  background: linear-gradient(135deg, var(--color-primary) 0%, #174d8a 100%);
  border-radius: var(--radius-xl);
  padding: var(--space-9) var(--space-8);
  text-align: center;
  color: #fff;
  position: relative;
  overflow: hidden; }

.newsletter-section::before {
  content: '';
  position: absolute;
  top: -40%;
  right: -20%;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.04);
  pointer-events: none; }

.newsletter-section__title {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  margin-bottom: var(--space-3);
  color: #fff; }

.newsletter-section__desc {
  font-size: var(--text-lg);
  opacity: 0.85;
  margin-bottom: var(--space-7);
  max-width: 480px;
  margin-left: auto;
  margin-right: auto;
  line-height: var(--leading-relaxed); }

.newsletter-form {
  display: flex;
  gap: var(--space-3);
  max-width: 460px;
  margin: 0 auto var(--space-4); }

.newsletter-form__input {
  flex: 1;
  padding: 12px var(--space-4);
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: var(--radius-md);
  color: #fff;
  font-family: var(--font-sans);
  font-size: var(--text-base);
  outline: none;
  transition: all var(--transition-fast); }

.newsletter-form__input::placeholder {
  color: rgba(255, 255, 255, 0.6); }

.newsletter-form__input:focus {
  background: rgba(255, 255, 255, 0.2);
  border-color: rgba(255, 255, 255, 0.6); }

.newsletter-form__submit {
  padding: 12px var(--space-6);
  background: #fff;
  color: var(--color-primary);
  border: none;
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition-fast); }

.newsletter-form__submit:hover {
  background: var(--color-surface-2);
  transform: translateY(-1px); }

.newsletter-section__privacy {
  font-size: var(--text-xs);
  opacity: 0.7; }

@media (max-width: 480px) {
  .newsletter-form {
    flex-direction: column; }
  .newsletter-section {
    padding: var(--space-7) var(--space-5); } }

/* =============================================================
   DairyCalc — Breadcrumb Component
   ============================================================= */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding: var(--space-3) 0; }

.breadcrumb__item {
  display: flex;
  align-items: center;
  gap: var(--space-2); }

.breadcrumb__link {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition-fast); }

.breadcrumb__link:hover {
  color: var(--color-primary);
  text-decoration: none; }

.breadcrumb__sep {
  color: var(--color-text-subtle);
  font-size: var(--text-xs); }

.breadcrumb__current {
  color: var(--color-text);
  font-weight: var(--weight-medium); }

/* =============================================================
   DairyCalc — Badge Component
   ============================================================= */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 2px var(--space-2);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  line-height: 1;
  white-space: nowrap; }

.badge--primary {
  background: var(--color-primary-light);
  color: var(--color-primary);
  border: 1px solid rgba(30, 95, 168, 0.2); }

.badge--success {
  background: var(--color-success-light);
  color: var(--color-success-text); }

.badge--warning {
  background: var(--color-warning-light);
  color: var(--color-warning-text); }

.badge--danger {
  background: var(--color-danger-light);
  color: var(--color-danger-text); }

.badge--accent {
  background: var(--color-accent-light);
  color: var(--color-accent); }

.badge--gray {
  background: var(--color-surface-2);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border); }

/* =============================================================
   DairyCalc — Alert Component
   ============================================================= */
.alert {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius-lg);
  border: 1px solid;
  font-size: var(--text-sm);
  line-height: 1.6; }

.alert__icon {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  margin-top: 1px; }

.alert--info {
  background: var(--color-info-light);
  border-color: var(--color-info);
  color: var(--color-info-text); }

.alert--success {
  background: var(--color-success-light);
  border-color: var(--color-success);
  color: var(--color-success-text); }

.alert--warning {
  background: var(--color-warning-light);
  border-color: var(--color-warning);
  color: var(--color-warning-text); }

.alert--danger {
  background: var(--color-danger-light);
  border-color: var(--color-danger);
  color: var(--color-danger-text); }

/* =============================================================
   DairyCalc — Search Modal
   ============================================================= */
.search-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  z-index: var(--z-modal);
  backdrop-filter: blur(4px);
  align-items: flex-start;
  justify-content: center;
  padding-top: 80px;
  padding-left: var(--space-4);
  padding-right: var(--space-4); }

.search-overlay.open {
  display: flex; }

.search-modal {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  width: 100%;
  max-width: 640px;
  overflow: hidden;
  max-height: calc(100vh - 160px);
  display: flex;
  flex-direction: column; }

.search-modal__input-row {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--color-border); }

.search-modal__icon {
  color: var(--color-text-muted);
  flex-shrink: 0; }

.search-modal__input {
  flex: 1;
  border: none;
  outline: none;
  font-family: var(--font-sans);
  font-size: var(--text-lg);
  color: var(--color-text);
  background: transparent; }

.search-modal__input::placeholder {
  color: var(--color-text-subtle); }

.search-modal__kbd {
  font-size: var(--text-xs);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 2px 7px;
  color: var(--color-text-subtle);
  font-family: var(--font-mono);
  cursor: pointer;
  flex-shrink: 0; }

.search-modal__results {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-3); }

.search-modal__empty {
  text-align: center;
  padding: var(--space-9) var(--space-5);
  color: var(--color-text-muted); }

.search-modal__empty-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto var(--space-4);
  color: var(--color-text-subtle); }

.search-result {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: var(--color-text);
  transition: background-color var(--transition-fast); }

.search-result:hover {
  background: var(--color-surface);
  text-decoration: none;
  color: var(--color-text); }

.search-result__icon {
  width: 36px;
  height: 36px;
  background: var(--color-surface);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  flex-shrink: 0; }

.search-result__title {
  font-weight: var(--weight-semibold);
  font-size: var(--text-sm);
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden; }

.search-result__excerpt {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden; }

.search-modal__footer {
  border-top: 1px solid var(--color-border);
  padding: var(--space-3) var(--space-5);
  display: flex;
  align-items: center;
  gap: var(--space-4);
  font-size: var(--text-xs);
  color: var(--color-text-subtle); }

.search-modal__shortcut {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1); }

.search-modal__shortcut kbd {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xs);
  padding: 1px 5px;
  font-family: var(--font-mono);
  font-size: 11px; }