/* ============================================================
   OilCalc Website — Main Stylesheet
   Mobile-first responsive · Dark/Light theme · 0.3s transitions
   ============================================================ */

/* ---------- CSS Custom Properties (Light Theme / Default) -- */
:root {
  /* Primary (blue) */
  --color-primary: #007AFF;
  --color-primary-hover: #0066D6;
  --color-primary-light: #E8F2FF;
  --color-primary-dark: #0055B3;

  /* Accent (warm) */
  --color-accent: #FF6B35;
  --color-accent-hover: #E55A2B;
  --color-accent-light: #FFF0E8;

  /* Neutrals */
  --color-bg: #FFFFFF;
  --color-bg-secondary: #F5F7FA;
  --color-bg-tertiary: #EBEDF0;
  --color-surface: #FFFFFF;
  --color-surface-hover: #F8F9FB;
  --color-text: #1C1C1E;
  --color-text-secondary: #636366;
  --color-text-tertiary: #AEAEB2;
  --color-border: #D1D1D6;
  --color-border-light: #E5E5EA;
  --color-shadow: rgba(0, 0, 0, 0.08);
  --color-shadow-hover: rgba(0, 0, 0, 0.14);

  /* Hero gradient */
  --hero-gradient-start: #007AFF;
  --hero-gradient-end: #5856D6;

  /* Navbar */
  --navbar-bg: rgba(255, 255, 255, 0.80);
  --navbar-border: rgba(0, 0, 0, 0.06);

  /* Card */
  --card-bg: #FFFFFF;
  --card-border: #E5E5EA;

  /* Best Value card (pricing) */
  --best-value-bg: #E8F2FF;
  --best-value-border: #007AFF;
  --best-value-badge-bg: #007AFF;
  --best-value-badge-text: #FFFFFF;

  /* FAQ */
  --faq-border: #D1D1D6;
  --faq-bg-hover: #F5F7FA;

  /* Footer */
  --footer-bg: #F5F7FA;
  --footer-text: #636366;

  /* Download buttons */
  --btn-download-bg: #1C1C1E;
  --btn-download-text: #FFFFFF;
  --btn-download-hover: #000000;

  /* Language toggle */
  --lang-btn-bg: transparent;
  --lang-btn-border: #D1D1D6;
  --lang-btn-text: #636366;
  --lang-btn-active-bg: #E8F2FF;
  --lang-btn-active-border: #007AFF;
  --lang-btn-active-text: #007AFF;

  /* Sizing */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-sm: 0 1px 3px var(--color-shadow);
  --shadow-md: 0 4px 12px var(--color-shadow);
  --shadow-lg: 0 8px 30px var(--color-shadow);
  --shadow-hover: 0 12px 40px var(--color-shadow-hover);
  --transition: 0.3s ease;
  --max-width: 1200px;
  --navbar-height: 64px;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display",
    "SF Pro Text", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Cascadia Code", "Fira Code", monospace;
  --line-height: 1.6;
  --line-height-heading: 1.25;
}

/* ---------- Dark Theme ------------------------------- */
@media (prefers-color-scheme: dark) {
  :root {
    --color-primary: #0A84FF;
    --color-primary-hover: #409CFF;
    --color-primary-light: #1A3A5C;
    --color-primary-dark: #66B0FF;

    --color-accent: #FF7B45;
    --color-accent-hover: #FF9466;
    --color-accent-light: #3D281E;

    --color-bg: #000000;
    --color-bg-secondary: #1C1C1E;
    --color-bg-tertiary: #2C2C2E;
    --color-surface: #1C1C1E;
    --color-surface-hover: #2C2C2E;
    --color-text: #F5F5F7;
    --color-text-secondary: #AEAEB2;
    --color-text-tertiary: #636366;
    --color-border: #38383A;
    --color-border-light: #2C2C2E;
    --color-shadow: rgba(0, 0, 0, 0.3);
    --color-shadow-hover: rgba(0, 0, 0, 0.5);

    --hero-gradient-start: #0A84FF;
    --hero-gradient-end: #5E5CE6;

    --navbar-bg: rgba(0, 0, 0, 0.78);
    --navbar-border: rgba(255, 255, 255, 0.08);

    --card-bg: #1C1C1E;
    --card-border: #38383A;

    --best-value-bg: #1A3A5C;
    --best-value-border: #0A84FF;
    --best-value-badge-bg: #0A84FF;
    --best-value-badge-text: #FFFFFF;

    --faq-border: #38383A;
    --faq-bg-hover: #2C2C2E;

    --footer-bg: #1C1C1E;
    --footer-text: #AEAEB2;

    --btn-download-bg: #FFFFFF;
    --btn-download-text: #1C1C1E;
    --btn-download-hover: #E5E5EA;

    --lang-btn-bg: transparent;
    --lang-btn-border: #38383A;
    --lang-btn-text: #AEAEB2;
    --lang-btn-active-bg: #1A3A5C;
    --lang-btn-active-border: #0A84FF;
    --lang-btn-active-text: #0A84FF;

    --color-shadow: rgba(0, 0, 0, 0.35);
    --color-shadow-hover: rgba(0, 0, 0, 0.55);
  }
}

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

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

body {
  font-family: var(--font-family);
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition), color var(--transition);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition);
}

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

a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 2px;
}

/* ---------- Typography ------------------------------- */
h1, h2, h3, h4, h5, h6 {
  line-height: var(--line-height-heading);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.5em;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
  margin-bottom: 1rem;
  color: var(--color-text-secondary);
}

small {
  font-size: 0.875rem;
}

strong, b {
  font-weight: 600;
}

/* ---------- Container -------------------------------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

@media (min-width: 768px) {
  .container {
    padding: 0 32px;
  }
}

@media (min-width: 1024px) {
  .container {
    padding: 0 40px;
  }
}

/* ---------- Buttons (generic) ------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-family: var(--font-family);
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.4;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #FFFFFF;
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

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

.btn-accent:hover {
  background-color: var(--color-accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-outline:hover {
  background-color: var(--color-primary);
  color: #FFFFFF;
  transform: translateY(-1px);
}

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

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

.btn-lg {
  padding: 16px 32px;
  font-size: 1.125rem;
  border-radius: var(--radius-lg);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.875rem;
  border-radius: var(--radius-sm);
}

/* ---------- Inputs ------------------------------------- */
.input,
.textarea,
select {
  width: 100%;
  padding: 12px 16px;
  font-family: var(--font-family);
  font-size: 1rem;
  color: var(--color-text);
  background-color: var(--color-surface);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition);
  outline: none;
}

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

.input:focus,
.textarea:focus,
select:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.15);
}

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

.textarea {
  min-height: 120px;
  resize: vertical;
}

label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  margin-bottom: 6px;
}

/* ---------- Navbar (sticky top, glassmorphism) --------- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--navbar-height);
  display: flex;
  align-items: center;
  background: var(--navbar-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--navbar-border);
  transition: background var(--transition), border-color var(--transition);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
}

.navbar-brand:hover {
  color: var(--color-primary);
}

.navbar-brand img,
.navbar-brand svg {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
}

.navbar-links {
  display: none;
  align-items: center;
  gap: 4px;
  list-style: none;
}

@media (min-width: 768px) {
  .navbar-links {
    display: flex;
  }
}

.navbar-links a {
  display: block;
  padding: 8px 16px;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  text-decoration: none;
}

.navbar-links a:hover,
.navbar-links a.active {
  color: var(--color-primary);
  background-color: var(--color-primary-light);
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Mobile hamburger */
.navbar-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}

@media (min-width: 768px) {
  .navbar-toggle {
    display: none;
  }
}

.navbar-toggle:hover {
  background: var(--color-bg-tertiary);
}

.navbar-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 2px;
  transition: all var(--transition);
}

/* Mobile menu overlay (JS toggles .open) */
.navbar-menu {
  display: none;
  position: fixed;
  top: var(--navbar-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--navbar-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  padding: 24px 20px;
  z-index: 999;
}

.navbar-menu.open {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.navbar-menu a {
  display: block;
  padding: 14px 16px;
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--color-text);
  border-radius: var(--radius-md);
  transition: all var(--transition);
  text-decoration: none;
}

.navbar-menu a:hover {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

/* ---------- Language Switcher ------------------------- */
.lang-switcher {
  display: flex;
  gap: 2px;
  background: var(--color-bg-tertiary);
  padding: 3px;
  border-radius: var(--radius-sm);
}

.lang-btn {
  padding: 6px 10px;
  font-size: 0.8125rem;
  font-weight: 500;
  font-family: var(--font-family);
  color: var(--lang-btn-text);
  background: var(--lang-btn-bg);
  border: 1px solid transparent;
  border-radius: 6px;
  cursor: pointer;
  transition: all var(--transition);
  line-height: 1.2;
}

.lang-btn:hover {
  color: var(--color-text);
}

.lang-btn.active {
  color: var(--lang-btn-active-text);
  background: var(--lang-btn-active-bg);
  border-color: var(--lang-btn-active-border);
}

/* ---------- Hero Section ------------------------------ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--navbar-height) + 40px) 20px 80px;
  background: linear-gradient(
    135deg,
    var(--hero-gradient-start) 0%,
    var(--hero-gradient-end) 100%
  );
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 50%, rgba(255, 255, 255, 0.10) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(255, 255, 255, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 50% 80%, rgba(255, 255, 255, 0.06) 0%, transparent 50%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

/* 内页小 Hero */
.hero.hero--small {
  min-height: auto;
  padding: calc(var(--navbar-height) + 32px) 20px 40px;
}

@media (min-width: 768px) {
  .hero.hero--small {
    padding: calc(var(--navbar-height) + 48px) 32px 56px;
  }
}

.hero h1 {
  font-size: 2.25rem;
  font-weight: 800;
  color: #FFFFFF;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}

.hero p {
  font-size: 1.125rem;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 36px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: center;
}

.hero-actions .btn {
  font-size: 1.0625rem;
  padding: 14px 28px;
}

.hero-actions .btn-primary {
  background: #FFFFFF;
  color: var(--color-primary);
}

.hero-actions .btn-primary:hover {
  background: rgba(255, 255, 255, 0.90);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
}

.hero-actions .btn-outline {
  border-color: rgba(255, 255, 255, 0.60);
  color: #FFFFFF;
}

.hero-actions .btn-outline:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: #FFFFFF;
}

@media (min-width: 768px) {
  .hero {
    min-height: 85vh;
    padding: calc(var(--navbar-height) + 80px) 32px 100px;
  }

  .hero h1 {
    font-size: 3.25rem;
  }

  .hero p {
    font-size: 1.25rem;
  }
}

@media (min-width: 1024px) {
  .hero h1 {
    font-size: 4rem;
  }
}

/* ---------- Section common --------------------------- */
.section {
  padding: 72px 0;
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 56px;
}

.section-header h2 {
  font-size: 1.875rem;
  margin-bottom: 12px;
}

.section-header p {
  font-size: 1.0625rem;
  color: var(--color-text-secondary);
}

@media (min-width: 768px) {
  .section {
    padding: 100px 0;
  }

  .section-header h2 {
    font-size: 2.375rem;
  }
}

/* ---------- Features Grid ----------------------------- */
.features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

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

@media (min-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ---------- Cards (generic) --------------------------- */
.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  border-color: var(--color-primary);
}

.card-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-radius: var(--radius-md);
  margin-bottom: 20px;
  font-size: 1.5rem;
}

.card h3 {
  font-size: 1.25rem;
  margin-bottom: 10px;
}

.card p {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  margin-bottom: 0;
}

/* ---------- Pricing Section --------------------------- */
.pricing-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  align-items: start;
}

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

.pricing-card {
  background: var(--card-bg);
  border: 1.5px solid var(--card-border);
  border-radius: var(--radius-xl);
  padding: 36px 28px;
  text-align: center;
  transition: all var(--transition);
  position: relative;
  display: flex;
  flex-direction: column;
}

.pricing-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.pricing-card .pricing-name {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.pricing-card .pricing-price {
  font-size: 3rem;
  font-weight: 800;
  color: var(--color-text);
  margin-bottom: 4px;
}

.pricing-card .pricing-period {
  font-size: 0.9375rem;
  color: var(--color-text-tertiary);
  margin-bottom: 24px;
}

.pricing-card .pricing-features {
  list-style: none;
  margin-bottom: 32px;
  flex: 1;
}

.pricing-card .pricing-features li {
  padding: 10px 0;
  border-bottom: 1px solid var(--color-border-light);
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
}

.pricing-card .pricing-features li:last-child {
  border-bottom: none;
}

.pricing-card .pricing-features li::before {
  content: '✓';
  color: var(--color-primary);
  font-weight: 700;
  margin-right: 10px;
}

/* Best Value card */
.pricing-card.best-value {
  border-color: var(--best-value-border);
  background: var(--best-value-bg);
  box-shadow: 0 0 0 2px var(--color-primary-light), var(--shadow-md);
  transform: scale(1.02);
  z-index: 1;
}

.pricing-card.best-value:hover {
  transform: scale(1.02) translateY(-6px);
}

.pricing-card.best-value .pricing-badge {
  display: inline-block;
  background: var(--best-value-badge-bg);
  color: var(--best-value-badge-text);
  font-size: 0.8125rem;
  font-weight: 700;
  padding: 6px 18px;
  border-radius: 20px;
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

@media (min-width: 768px) {
  .pricing-card.best-value {
    transform: scale(1.05);
  }

  .pricing-card.best-value:hover {
    transform: scale(1.05) translateY(-6px);
  }
}

/* ---------- FAQ (accordion) --------------------------- */
.faq-list {
  max-width: 720px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--faq-border);
  transition: border-color var(--transition);
}

.faq-item:first-child {
  border-top: 1px solid var(--faq-border);
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 20px 16px;
  font-family: var(--font-family);
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  color: var(--color-text);
  background: none;
  border: none;
  cursor: pointer;
  gap: 16px;
  transition: all var(--transition);
  border-radius: 0;
}

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

.faq-question:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: -2px;
}

.faq-question .faq-icon {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition);
  color: var(--color-text-tertiary);
}

.faq-item.open .faq-question .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  padding: 0 16px;
}

.faq-item.open .faq-answer {
  max-height: 600px;
  padding: 0 16px 24px;
}

.faq-answer p {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: 0;
}

/* ---------- App Store Download Buttons ---------------- */
.download-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
}

.download-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 24px;
  background: var(--btn-download-bg);
  color: var(--btn-download-text);
  border-radius: var(--radius-md);
  text-decoration: none;
  font-family: var(--font-family);
  transition: all var(--transition);
  min-width: 180px;
}

.download-btn:hover {
  background: var(--btn-download-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  color: var(--btn-download-text);
}

.download-btn .download-icon {
  font-size: 1.75rem;
  line-height: 1;
}

.download-btn .download-label {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.download-btn .download-label small {
  font-size: 0.6875rem;
  opacity: 0.65;
  font-weight: 400;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.download-btn .download-label strong {
  font-size: 1rem;
  font-weight: 600;
}

/* ---------- Footer ------------------------------------ */
.footer {
  background: var(--footer-bg);
  border-top: 1px solid var(--color-border-light);
  padding: 48px 0 32px;
  transition: background var(--transition), border-color var(--transition);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  margin-bottom: 40px;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr 1fr;
  }
}

.footer-brand p {
  font-size: 0.875rem;
  color: var(--footer-text);
  margin-top: 12px;
  max-width: 300px;
}

.footer h4 {
  font-size: 0.8125rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-tertiary);
  margin-bottom: 16px;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 10px;
}

.footer-links a {
  font-size: 0.875rem;
  color: var(--footer-text);
  transition: color var(--transition);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--color-primary);
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border-light);
  font-size: 0.8125rem;
  color: var(--color-text-tertiary);
  text-align: center;
}

@media (min-width: 768px) {
  .footer-bottom {
    flex-direction: row;
    justify-content: space-between;
  }
}

.footer-social {
  display: flex;
  gap: 16px;
}

.footer-social a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  color: var(--color-text-tertiary);
  background: var(--color-bg-tertiary);
  transition: all var(--transition);
  text-decoration: none;
  font-size: 1rem;
}

.footer-social a:hover {
  color: var(--color-primary);
  background: var(--color-primary-light);
  transform: translateY(-2px);
}

/* ---------- Utility Classes --------------------------- */
.text-center { text-align: center; }
.text-left   { text-align: left; }
.text-right  { text-align: right; }

.flex       { display: flex; }
.flex-col   { flex-direction: column; }
.flex-wrap  { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-8   { gap: 8px; }
.gap-12  { gap: 12px; }
.gap-16  { gap: 16px; }
.gap-24  { gap: 24px; }
.gap-32  { gap: 32px; }

.mt-8   { margin-top: 8px; }
.mt-16  { margin-top: 16px; }
.mt-24  { margin-top: 24px; }
.mt-32  { margin-top: 32px; }
.mt-48  { margin-top: 48px; }
.mb-8   { margin-bottom: 8px; }
.mb-16  { margin-bottom: 16px; }
.mb-24  { margin-bottom: 24px; }
.mb-32  { margin-bottom: 32px; }

.w-full { width: 100%; }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* ---------- Reduced Motion ---------------------------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}