/* ==========================================================================
   StackFox Studio (stackgfox.top) - Official Stylesheet
   Theme System: Twilight Night (暗夜萤火) & Morning Mist (晨曦自然)
   ========================================================================== */

:root, [data-theme="dark"] {
  /* Dark Twilight Palette */
  --bg-space: #051412;
  --bg-deep: #071F1D;
  --bg-card: rgba(13, 44, 40, 0.65);
  --bg-card-hover: rgba(18, 58, 52, 0.85);
  --bg-glass: rgba(255, 255, 255, 0.04);
  --bg-glass-elevated: rgba(255, 255, 255, 0.08);

  /* Borders & Dividers */
  --border-subtle: rgba(120, 212, 157, 0.12);
  --border-glow: rgba(120, 212, 157, 0.35);
  --border-gold: rgba(255, 212, 90, 0.35);

  /* Accents & Brand Lighting */
  --mint-light: #DDF7D5;
  --mint-primary: #78D49D;
  --mint-vivid: #10B981;
  --gold-light: #FFF3A3;
  --gold-primary: #FFD45A;
  --gold-amber: #F59E0B;
  --gold-glow: rgba(255, 212, 90, 0.4);

  /* Typography Colors */
  --text-main: #F4FDF9;
  --text-secondary: #C3DFD8;
  --text-muted: #7E9E96;
  --text-dark: #071F1D;

  /* Surfaces & Elevation */
  --shadow-card: 0 20px 50px -10px rgba(2, 18, 16, 0.6), 0 0 0 1px var(--border-subtle);
  --shadow-glow-mint: 0 0 30px rgba(120, 212, 157, 0.2);
  --shadow-glow-gold: 0 0 35px rgba(255, 212, 90, 0.28);
  --header-bg: rgba(7, 31, 29, 0.85);
  --footer-bg: #041210;

  /* Radii */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 36px;
  --radius-full: 9999px;

  /* Transitions */
  --ease-spring: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);

  /* Layout */
  --max-width: 1200px;
  --nav-height: 76px;
}

/* ==========================================================================
   Daytime / Morning Mist Theme (晨曦明媚模式)
   ========================================================================== */
[data-theme="light"] {
  --bg-space: #F4F9F6;
  --bg-deep: #EAF4EE;
  --bg-card: rgba(255, 255, 255, 0.82);
  --bg-card-hover: rgba(255, 255, 255, 0.98);
  --bg-glass: rgba(16, 185, 129, 0.04);
  --bg-glass-elevated: rgba(16, 185, 129, 0.08);

  --border-subtle: rgba(16, 185, 129, 0.15);
  --border-glow: rgba(16, 185, 129, 0.38);
  --border-gold: rgba(217, 119, 6, 0.32);

  --mint-light: #0B4D3F;
  --mint-primary: #059669;
  --mint-vivid: #047857;
  --gold-light: #92400E;
  --gold-primary: #D97706;
  --gold-amber: #B45309;
  --gold-glow: rgba(217, 119, 6, 0.25);

  --text-main: #0B2824;
  --text-secondary: #2C524A;
  --text-muted: #5E8077;
  --text-dark: #071F1D;

  --shadow-card: 0 20px 45px -12px rgba(16, 185, 129, 0.12), 0 4px 12px rgba(0, 0, 0, 0.04), 0 0 0 1px var(--border-subtle);
  --shadow-glow-mint: 0 0 30px rgba(16, 185, 129, 0.15);
  --shadow-glow-gold: 0 0 35px rgba(245, 158, 11, 0.2);
  --header-bg: rgba(244, 249, 246, 0.9);
  --footer-bg: #E6F0EB;
}

/* ==========================================================================
   CSS Reset & Base
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-space);
  color: var(--text-main);
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "PingFang SC", "Segoe UI", Roboto, sans-serif;
  line-height: 1.68;
  color: var(--text-main);
  background-color: var(--bg-space);
  position: relative;
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

a {
  color: inherit;
  text-decoration: none;
  transition: all 0.2s var(--ease-smooth);
}

button {
  font-family: inherit;
  border: none;
  outline: none;
  cursor: pointer;
  background: none;
}

img, svg {
  display: block;
  max-width: 100%;
}

/* ==========================================================================
   Background Ambient Lighting & Firefly Canvas
   ========================================================================== */
.ambient-lighting {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.gradient-sphere {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.45;
  transition: transform 10s ease-in-out, background 0.4s ease;
  animation: floatAmbient 20s infinite alternate ease-in-out;
}

[data-theme="light"] .gradient-sphere {
  opacity: 0.6;
}

.sphere-1 {
  top: -15%;
  left: 20%;
  width: 60vw;
  height: 60vw;
  max-width: 800px;
  max-height: 800px;
  background: radial-gradient(circle, rgba(18, 72, 63, 0.7) 0%, rgba(7, 31, 29, 0) 70%);
}

[data-theme="light"] .sphere-1 {
  background: radial-gradient(circle, rgba(16, 185, 129, 0.18) 0%, rgba(244, 249, 246, 0) 70%);
}

.sphere-2 {
  top: 40%;
  right: -10%;
  width: 50vw;
  height: 50vw;
  max-width: 650px;
  max-height: 650px;
  background: radial-gradient(circle, rgba(245, 158, 11, 0.15) 0%, rgba(7, 31, 29, 0) 70%);
  animation-delay: -7s;
}

[data-theme="light"] .sphere-2 {
  background: radial-gradient(circle, rgba(245, 158, 11, 0.12) 0%, rgba(244, 249, 246, 0) 70%);
}

.sphere-3 {
  bottom: 5%;
  left: -10%;
  width: 55vw;
  height: 55vw;
  max-width: 700px;
  max-height: 700px;
  background: radial-gradient(circle, rgba(16, 185, 129, 0.18) 0%, rgba(7, 31, 29, 0) 70%);
  animation-delay: -12s;
}

[data-theme="light"] .sphere-3 {
  background: radial-gradient(circle, rgba(52, 211, 153, 0.15) 0%, rgba(244, 249, 246, 0) 70%);
}

@keyframes floatAmbient {
  0% { transform: translateY(0) scale(1); }
  50% { transform: translateY(40px) scale(1.08) translateX(20px); }
  100% { transform: translateY(-30px) scale(0.95) translateX(-20px); }
}

#firefly-canvas {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  z-index: 1;
  pointer-events: none;
}

.app-wrapper {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ==========================================================================
   Typography & Shared Classes
   ========================================================================== */
.serif-display {
  font-family: ui-serif, "Songti SC", "STSong", "Noto Serif SC", serif;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.hero-title-line {
  display: block;
  white-space: nowrap;
}

.title-chunk {
  display: inline-block;
}

.mobile-drawer-cta {
  display: none;
}

.tag-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  background: rgba(120, 212, 157, 0.1);
  border: 1px solid rgba(120, 212, 157, 0.25);
  color: var(--mint-light);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  backdrop-filter: blur(10px);
  transition: all 0.3s ease;
}

[data-theme="light"] .tag-badge {
  background: rgba(16, 185, 129, 0.08);
  border-color: rgba(16, 185, 129, 0.22);
  color: #065F46;
}

.tag-badge.gold {
  background: rgba(255, 212, 90, 0.1);
  border-color: rgba(255, 212, 90, 0.3);
  color: var(--gold-light);
}

[data-theme="light"] .tag-badge.gold {
  background: rgba(217, 119, 6, 0.08);
  border-color: rgba(217, 119, 6, 0.22);
  color: #92400E;
}

.tag-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--gold-primary);
  box-shadow: 0 0 10px var(--gold-primary);
  animation: pulseDot 2s infinite ease-in-out;
}

@keyframes pulseDot {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.4); opacity: 0.6; }
}

.gradient-text-mint {
  background: linear-gradient(135deg, #F3FFE8 0%, #78D49D 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

[data-theme="light"] .gradient-text-mint {
  background: linear-gradient(135deg, #065F46 0%, #059669 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.gradient-text-gold {
  background: linear-gradient(135deg, #FFF6B8 0%, #FFD45A 60%, #F59E0B 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

[data-theme="light"] .gradient-text-gold {
  background: linear-gradient(135deg, #B45309 0%, #D97706 50%, #047857 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-header {
  text-align: center;
  max-width: 780px;
  margin: 0 auto 60px;
}

.section-header .tag-badge {
  margin-bottom: 16px;
}

.section-title {
  font-size: clamp(2rem, 3.8vw, 3rem);
  line-height: 1.22;
  margin-bottom: 18px;
}

.section-desc {
  font-size: clamp(1rem, 1.2vw, 1.125rem);
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Button System */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 28px;
  border-radius: var(--radius-full);
  font-size: 0.9375rem;
  font-weight: 600;
  transition: all 0.28s var(--ease-spring);
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: linear-gradient(135deg, #FFD45A 0%, #F59E0B 100%);
  color: #071F1D;
  box-shadow: 0 4px 20px rgba(245, 158, 11, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(245, 158, 11, 0.55);
}

[data-theme="light"] .btn-primary {
  background: linear-gradient(135deg, #F59E0B 0%, #D97706 100%);
  color: #FFFFFF;
  box-shadow: 0 4px 18px rgba(217, 119, 6, 0.3);
}

.btn-mint {
  background: linear-gradient(135deg, #78D49D 0%, #10B981 100%);
  color: #071F1D;
  box-shadow: 0 4px 20px rgba(16, 185, 129, 0.3);
}

.btn-mint:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(16, 185, 129, 0.5);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-main);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(12px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--border-glow);
  transform: translateY(-2px);
}

[data-theme="light"] .btn-secondary {
  background: rgba(16, 185, 129, 0.06);
  color: #0B2824;
  border-color: rgba(16, 185, 129, 0.2);
}

[data-theme="light"] .btn-secondary:hover {
  background: rgba(16, 185, 129, 0.12);
  border-color: rgba(16, 185, 129, 0.38);
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 100;
  transition: background 0.3s ease, border-color 0.3s ease, backdrop-filter 0.3s ease;
  border-bottom: 1px solid transparent;
}

.site-header.scrolled {
  background: var(--header-bg);
  backdrop-filter: blur(20px);
  border-bottom-color: var(--border-subtle);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 1.1875rem;
  letter-spacing: -0.01em;
}

.brand-logo-img {
  width: 40px;
  height: 40px;
  object-fit: contain;
  filter: drop-shadow(0 2px 10px rgba(255, 212, 90, 0.4));
  transition: transform 0.25s ease;
}

[data-theme="light"] .brand-logo-img {
  filter: drop-shadow(0 2px 8px rgba(16, 185, 129, 0.25));
}

.brand-logo:hover .brand-logo-img {
  transform: scale(1.08) rotate(3deg);
}

.brand-text {
  display: flex;
  flex-direction: column;
}

.brand-title {
  color: var(--text-main);
  line-height: 1.15;
}

.brand-sub {
  font-size: 0.6875rem;
  color: var(--mint-primary);
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-link {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  font-weight: 500;
  position: relative;
  padding: 6px 0;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-main);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gold-primary);
  transition: width 0.25s ease;
  border-radius: 2px;
}

.nav-link:hover::after, .nav-link.active::after {
  width: 100%;
}

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

/* Theme Toggle Button */
.theme-toggle-btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--border-subtle);
  color: var(--text-main);
  cursor: pointer;
  transition: all 0.25s var(--ease-spring);
  position: relative;
  overflow: hidden;
}

.theme-toggle-btn:hover {
  background: rgba(255, 255, 255, 0.16);
  border-color: var(--border-glow);
  transform: rotate(15deg) scale(1.06);
}

[data-theme="light"] .theme-toggle-btn {
  background: rgba(16, 185, 129, 0.08);
  border-color: rgba(16, 185, 129, 0.22);
  color: #0B2824;
}

[data-theme="light"] .theme-toggle-btn:hover {
  background: rgba(16, 185, 129, 0.15);
  border-color: rgba(16, 185, 129, 0.38);
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}

.menu-toggle span {
  width: 24px;
  height: 2px;
  background: var(--text-main);
  transition: all 0.3s ease;
  border-radius: 2px;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section {
  padding: calc(var(--nav-height) + 60px) 0 80px;
  position: relative;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.25fr 0.75fr;
  gap: 56px;
  align-items: center;
}

.hero-content {
  max-width: 680px;
}

.hero-title {
  font-size: clamp(2.1rem, 3.2vw, 3.25rem);
  line-height: 1.24;
  margin: 20px 0 24px;
}

.hero-desc {
  font-size: clamp(1.05rem, 1.3vw, 1.2rem);
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 36px;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 48px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  padding-top: 32px;
  border-top: 1px solid var(--border-subtle);
}

.stat-item {
  display: flex;
  flex-direction: column;
}

.stat-number {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--mint-light);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* Hero Mockup Visual */
.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.mockup-container {
  width: 100%;
  max-width: 380px;
  position: relative;
}

.glow-halo-behind {
  position: absolute;
  inset: -20px;
  background: radial-gradient(circle, rgba(255, 212, 90, 0.25) 0%, rgba(120, 212, 157, 0.15) 50%, transparent 70%);
  filter: blur(30px);
  z-index: 0;
  animation: breatheHalo 6s infinite alternate ease-in-out;
}

[data-theme="light"] .glow-halo-behind {
  background: radial-gradient(circle, rgba(245, 158, 11, 0.2) 0%, rgba(16, 185, 129, 0.15) 50%, transparent 70%);
}

@keyframes breatheHalo {
  0% { transform: scale(0.95); opacity: 0.6; }
  100% { transform: scale(1.08); opacity: 0.9; }
}

.phone-mockup-frame {
  position: relative;
  z-index: 1;
  background: #082622;
  border: 4px solid rgba(255, 255, 255, 0.15);
  border-radius: 44px;
  padding: 12px;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.6), inset 0 0 0 1px rgba(120, 212, 157, 0.2);
  transition: all 0.3s ease;
}

[data-theme="light"] .phone-mockup-frame {
  background: #FFFFFF;
  border-color: rgba(16, 185, 129, 0.25);
  box-shadow: 0 25px 60px rgba(16, 185, 129, 0.18), inset 0 0 0 1px rgba(16, 185, 129, 0.1);
}

.phone-screen {
  background: linear-gradient(180deg, #0D3731 0%, #071F1D 100%);
  border-radius: 34px;
  overflow: hidden;
  padding: 24px 20px;
  display: flex;
  flex-direction: column;
  position: relative;
}

[data-theme="light"] .phone-screen {
  background: linear-gradient(180deg, #E6F5ED 0%, #D4EFE1 100%);
}

.phone-status-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.mockup-card {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(120, 212, 157, 0.2);
  border-radius: 24px;
  padding: 28px 20px;
  text-align: center;
  margin-bottom: 20px;
  position: relative;
  backdrop-filter: blur(15px);
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.3);
}

[data-theme="light"] .mockup-card {
  background: rgba(255, 255, 255, 0.88);
  border-color: rgba(16, 185, 129, 0.25);
  box-shadow: 0 10px 25px rgba(16, 185, 129, 0.1);
}

.mockup-word {
  font-size: 1.85rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: 0.02em;
}

.mockup-phonetic {
  font-size: 0.9375rem;
  color: var(--gold-primary);
  margin: 6px 0 14px;
}

.mockup-meaning {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
  background: rgba(7, 31, 29, 0.6);
  padding: 10px;
  border-radius: 12px;
}

[data-theme="light"] .mockup-meaning {
  background: rgba(230, 245, 238, 0.9);
}

.mockup-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.mockup-btn {
  padding: 10px;
  border-radius: 14px;
  font-size: 0.8125rem;
  font-weight: 700;
  text-align: center;
}

.mockup-btn.primary {
  background: var(--gold-primary);
  color: #071F1D;
}

[data-theme="light"] .mockup-btn.primary {
  color: #FFFFFF;
}

.mockup-btn.outline {
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}

.floating-badge {
  position: absolute;
  padding: 10px 16px;
  border-radius: 18px;
  background: rgba(7, 31, 29, 0.85);
  border: 1px solid var(--border-glow);
  backdrop-filter: blur(16px);
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.4);
  display: flex;
  align-items: center;
  gap: 10px;
  z-index: 2;
  transition: all 0.3s ease;
}

[data-theme="light"] .floating-badge {
  background: rgba(255, 255, 255, 0.92);
  border-color: rgba(16, 185, 129, 0.28);
  box-shadow: 0 15px 35px rgba(16, 185, 129, 0.12);
}

.floating-badge.top-left {
  top: 15%;
  left: -25px;
  animation: floatSlow 5s infinite ease-in-out;
}

.floating-badge.bottom-right {
  bottom: 5%;
  right: -28px;
  animation: floatSlow 6s infinite ease-in-out 1s;
}

@keyframes floatSlow {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

/* ==========================================================================
   Flagship Showcase Section: 萤火花园
   ========================================================================== */
.flagship-section {
  padding: 100px 0;
  position: relative;
}

.flagship-card-main {
  background: linear-gradient(135deg, rgba(13, 44, 40, 0.75) 0%, rgba(7, 26, 24, 0.95) 100%);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-xl);
  padding: 56px 48px;
  box-shadow: var(--shadow-card);
  position: relative;
  overflow: hidden;
  transition: all 0.3s ease;
}

[data-theme="light"] .flagship-card-main {
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.95) 0%, rgba(236, 248, 242, 0.95) 100%);
  border-color: rgba(16, 185, 129, 0.25);
  box-shadow: 0 20px 50px -10px rgba(16, 185, 129, 0.15);
}

.flagship-card-main::before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(255, 212, 90, 0.12) 0%, transparent 60%);
  pointer-events: none;
}

[data-theme="light"] .flagship-card-main::before {
  background: radial-gradient(circle, rgba(245, 158, 11, 0.08) 0%, transparent 60%);
}

.flagship-intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
  margin-bottom: 56px;
}

.flagship-badge-row {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
}

.flagship-app-icon {
  width: 72px;
  height: 72px;
  object-fit: contain;
  filter: drop-shadow(0 10px 25px rgba(255, 212, 90, 0.4));
  transition: transform 0.3s ease;
}

[data-theme="light"] .flagship-app-icon {
  filter: drop-shadow(0 8px 20px rgba(16, 185, 129, 0.25));
}

.flagship-app-icon:hover {
  transform: scale(1.08) rotate(-4deg);
}

.flagship-pillars-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.pillar-card {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  transition: all 0.3s var(--ease-spring);
  position: relative;
}

[data-theme="light"] .pillar-card {
  background: rgba(255, 255, 255, 0.85);
  border-color: rgba(16, 185, 129, 0.15);
  box-shadow: 0 4px 15px rgba(0,0,0,0.02);
}

.pillar-card:hover {
  background: rgba(255, 255, 255, 0.07);
  border-color: var(--border-glow);
  transform: translateY(-6px);
  box-shadow: 0 15px 35px rgba(2, 20, 18, 0.4);
}

[data-theme="light"] .pillar-card:hover {
  background: #FFFFFF;
  border-color: rgba(16, 185, 129, 0.35);
  box-shadow: 0 14px 35px rgba(16, 185, 129, 0.12);
}

.pillar-icon-box {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
  background: rgba(120, 212, 157, 0.1);
  border: 1px solid rgba(120, 212, 157, 0.2);
  color: var(--mint-light);
}

[data-theme="light"] .pillar-icon-box {
  background: rgba(16, 185, 129, 0.1);
  border-color: rgba(16, 185, 129, 0.2);
}

.pillar-icon-box.gold {
  background: rgba(255, 212, 90, 0.1);
  border-color: rgba(255, 212, 90, 0.25);
  color: var(--gold-primary);
}

[data-theme="light"] .pillar-icon-box.gold {
  background: rgba(245, 158, 11, 0.1);
  border-color: rgba(245, 158, 11, 0.2);
}

.pillar-title {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-main);
}

.pillar-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ==========================================================================
   Interactive Simulator Section (在线体验区)
   ========================================================================== */
.simulator-section {
  padding: 90px 0;
  position: relative;
}

.simulator-box {
  background: linear-gradient(180deg, #0A2B27 0%, #061A18 100%);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-xl);
  padding: 48px;
  box-shadow: var(--shadow-card), var(--shadow-glow-gold);
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: 48px;
  align-items: center;
  transition: all 0.3s ease;
}

[data-theme="light"] .simulator-box {
  background: linear-gradient(180deg, #FFFFFF 0%, #EDF7F2 100%);
  border-color: rgba(16, 185, 129, 0.25);
  box-shadow: 0 20px 50px -10px rgba(16, 185, 129, 0.12);
}

.sim-info {
  display: flex;
  flex-direction: column;
}

.sim-garden-stats {
  display: flex;
  gap: 24px;
  margin-top: 24px;
  padding: 16px 20px;
  background: rgba(255, 255, 255, 0.04);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  transition: all 0.3s ease;
}

[data-theme="light"] .sim-garden-stats {
  background: rgba(16, 185, 129, 0.06);
  border-color: rgba(16, 185, 129, 0.15);
}

.sim-stat {
  display: flex;
  flex-direction: column;
}

.sim-stat-val {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--gold-primary);
}

.sim-stat-key {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Interactive Card Component */
.interactive-card-arena {
  background: rgba(18, 54, 49, 0.6);
  border: 1px solid rgba(120, 212, 157, 0.3);
  border-radius: 28px;
  padding: 36px 32px;
  position: relative;
  backdrop-filter: blur(20px);
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.5);
  transition: all 0.4s var(--ease-spring);
}

[data-theme="light"] .interactive-card-arena {
  background: rgba(255, 255, 255, 0.95);
  border-color: rgba(16, 185, 129, 0.25);
  box-shadow: 0 15px 40px rgba(16, 185, 129, 0.1);
}

.interactive-card-arena.illuminated {
  border-color: var(--gold-primary);
  box-shadow: 0 0 50px rgba(255, 212, 90, 0.35), 0 20px 60px rgba(0, 0, 0, 0.6);
}

[data-theme="light"] .interactive-card-arena.illuminated {
  box-shadow: 0 0 40px rgba(245, 158, 11, 0.3), 0 15px 40px rgba(0, 0, 0, 0.08);
}

.word-stage-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.word-level-tag {
  font-size: 0.75rem;
  padding: 4px 10px;
  background: rgba(255, 212, 90, 0.15);
  color: var(--gold-primary);
  border-radius: var(--radius-full);
  font-weight: 700;
}

[data-theme="light"] .word-level-tag {
  background: rgba(217, 119, 6, 0.1);
  color: #92400E;
}

.word-display-main {
  text-align: center;
  margin-bottom: 28px;
}

.word-title-text {
  font-size: 2.35rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: 0.02em;
  margin-bottom: 6px;
}

.word-phonetic-text {
  font-size: 1.05rem;
  color: var(--mint-primary);
  font-family: ui-sans-serif, system-ui;
}

.word-meaning-box {
  min-height: 70px;
  background: rgba(7, 31, 29, 0.7);
  border-radius: var(--radius-md);
  padding: 14px 18px;
  margin-bottom: 24px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  border: 1px solid var(--border-subtle);
  transition: all 0.3s ease;
}

[data-theme="light"] .word-meaning-box {
  background: rgba(240, 248, 244, 0.85);
  border-color: rgba(16, 185, 129, 0.18);
}

.word-meaning-cn {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-main);
}

.word-sentence-en {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  margin-top: 4px;
  font-style: italic;
}

.sim-btn-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 12px;
}

.sim-action-btn {
  padding: 14px 18px;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.2s var(--ease-spring);
}

.sim-action-btn.remember {
  background: linear-gradient(135deg, #FFD45A 0%, #F59E0B 100%);
  color: #071F1D;
  box-shadow: 0 4px 15px rgba(245, 158, 11, 0.4);
}

[data-theme="light"] .sim-action-btn.remember {
  background: linear-gradient(135deg, #F59E0B 0%, #D97706 100%);
  color: #FFFFFF;
}

.sim-action-btn.remember:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(245, 158, 11, 0.6);
}

.sim-action-btn.hint {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-main);
  border: 1px solid var(--border-subtle);
}

[data-theme="light"] .sim-action-btn.hint {
  background: rgba(16, 185, 129, 0.08);
  color: #0B2824;
  border-color: rgba(16, 185, 129, 0.22);
}

.sim-action-btn.hint:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: var(--border-glow);
}

.particle-burst-container {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  border-radius: 28px;
}

/* ==========================================================================
   Product Matrix Section (教育产品矩阵)
   ========================================================================== */
.matrix-section {
  padding: 100px 0;
}

.matrix-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.matrix-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: 36px 30px;
  display: flex;
  flex-direction: column;
  transition: all 0.3s var(--ease-spring);
  backdrop-filter: blur(16px);
  position: relative;
  overflow: hidden;
}

[data-theme="light"] .matrix-card {
  background: rgba(255, 255, 255, 0.88);
  border-color: rgba(16, 185, 129, 0.18);
  box-shadow: 0 10px 30px -10px rgba(16, 185, 129, 0.08);
}

.matrix-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-glow);
  transform: translateY(-6px);
  box-shadow: var(--shadow-card);
}

[data-theme="light"] .matrix-card:hover {
  background: #FFFFFF;
  border-color: rgba(16, 185, 129, 0.35);
  box-shadow: 0 18px 45px -10px rgba(16, 185, 129, 0.16);
}

.matrix-card-tag {
  align-self: flex-start;
  margin-bottom: 20px;
}

.matrix-card-title {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-main);
}

.matrix-card-desc {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.68;
  margin-bottom: 24px;
}

.matrix-feature-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: auto;
  padding-top: 20px;
  border-top: 1px solid var(--border-subtle);
}

.matrix-feature-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.matrix-feature-item svg {
  color: var(--mint-primary);
  flex-shrink: 0;
}

/* ==========================================================================
   Engineering & Values Section (研发理念与技术底座)
   ========================================================================== */
.values-section {
  padding: 100px 0;
  position: relative;
}

.values-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.value-card {
  background: rgba(13, 44, 40, 0.5);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 36px;
  display: flex;
  gap: 24px;
  backdrop-filter: blur(16px);
  transition: all 0.3s ease;
}

[data-theme="light"] .value-card {
  background: rgba(255, 255, 255, 0.82);
  border-color: rgba(16, 185, 129, 0.15);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.03);
}

.value-card:hover {
  border-color: var(--border-glow);
  background: rgba(18, 56, 50, 0.7);
  transform: translateY(-4px);
}

[data-theme="light"] .value-card:hover {
  background: #FFFFFF;
  border-color: rgba(16, 185, 129, 0.35);
}

.value-icon-wrapper {
  width: 56px;
  height: 56px;
  border-radius: 16px;
  background: rgba(120, 212, 157, 0.1);
  border: 1px solid rgba(120, 212, 157, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: var(--mint-light);
}

[data-theme="light"] .value-icon-wrapper {
  background: rgba(16, 185, 129, 0.1);
  border-color: rgba(16, 185, 129, 0.2);
  color: var(--mint-vivid);
}

.value-content h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text-main);
}

.value-content p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ==========================================================================
   About StackFox Section (关于栈狐工作室)
   ========================================================================== */
.about-section {
  padding: 90px 0;
  position: relative;
}

.about-banner {
  background: radial-gradient(circle at 80% 20%, rgba(120, 212, 157, 0.15) 0%, transparent 50%),
              radial-gradient(circle at 20% 80%, rgba(255, 212, 90, 0.1) 0%, transparent 40%),
              #0B2E29;
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-xl);
  padding: 60px 48px;
  display: grid;
  grid-template-columns: 1fr 0.9fr;
  gap: 48px;
  align-items: center;
  transition: all 0.3s ease;
}

[data-theme="light"] .about-banner {
  background: linear-gradient(135deg, #FFFFFF 0%, #EBF5F0 100%);
  border-color: rgba(16, 185, 129, 0.25);
  box-shadow: 0 20px 50px rgba(16, 185, 129, 0.1);
}

.about-text h2 {
  font-size: clamp(1.8rem, 2.8vw, 2.4rem);
  line-height: 1.25;
  margin-bottom: 18px;
}

.about-text p {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 16px;
}

.about-cards-sub {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.about-mini-card {
  background: rgba(7, 31, 29, 0.7);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 20px;
  text-align: center;
  transition: all 0.3s ease;
}

[data-theme="light"] .about-mini-card {
  background: rgba(255, 255, 255, 0.92);
  border-color: rgba(16, 185, 129, 0.18);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.02);
}

.about-mini-card strong {
  display: block;
  font-size: 1.125rem;
  color: var(--gold-primary);
  margin-bottom: 4px;
}

.about-mini-card span {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Footer & Legal Info
   ========================================================================== */
.site-footer {
  background: var(--footer-bg);
  border-top: 1px solid var(--border-subtle);
  padding: 70px 0 40px;
  margin-top: auto;
  position: relative;
  z-index: 10;
  transition: background 0.3s ease, border-color 0.3s ease;
}

.footer-top-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
  gap: 40px;
  margin-bottom: 50px;
}

.footer-brand p {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-top: 14px;
  max-width: 320px;
}

.footer-col-title {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 18px;
  letter-spacing: 0.04em;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.footer-links a:hover {
  color: var(--gold-primary);
  transform: translateX(3px);
}

.footer-contact-info {
  font-size: 0.875rem;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-bottom-bar {
  padding-top: 30px;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8125rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: 16px;
}

.icp-link {
  color: var(--text-muted);
  transition: color 0.2s ease;
}

.icp-link:hover {
  color: var(--mint-primary);
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 40px;
  }
  .hero-content {
    max-width: 100%;
    margin: 0 auto;
  }
  .hero-cta-group {
    justify-content: center;
  }
  .hero-stats {
    max-width: 480px;
    margin: 0 auto;
  }
  .flagship-intro-grid {
    grid-template-columns: 1fr;
    gap: 30px;
  }
  .flagship-pillars-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .simulator-box {
    grid-template-columns: 1fr;
    gap: 36px;
    padding: 32px;
  }
  .matrix-grid {
    grid-template-columns: 1fr;
  }
  .about-banner {
    grid-template-columns: 1fr;
    padding: 40px 30px;
  }
  .footer-top-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  :root {
    --nav-height: 64px;
  }
  .container {
    padding: 0 18px;
  }
  /* Header clean layout on mobile */
  .site-header {
    height: var(--nav-height);
  }
  .nav-cta-btn {
    display: none !important;
  }
  .nav-actions {
    gap: 8px;
  }
  .theme-toggle-btn {
    width: 38px;
    height: 38px;
  }
  .brand-logo {
    gap: 8px;
  }
  .brand-logo-img {
    width: 34px;
    height: 34px;
  }
  .brand-title {
    font-size: 1.05rem;
  }
  .brand-sub {
    font-size: 0.625rem;
    letter-spacing: 0.08em;
  }
  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--header-bg);
    backdrop-filter: blur(25px);
    flex-direction: column;
    padding: 24px 20px 30px;
    gap: 16px;
    border-bottom: 1px solid var(--border-subtle);
    transform: translateY(-150%);
    transition: transform 0.35s var(--ease-spring);
    pointer-events: none;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
  }
  .nav-links.open {
    transform: translateY(0);
    pointer-events: all;
  }
  .mobile-drawer-cta {
    display: block;
    width: 100%;
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid var(--border-subtle);
  }
  .menu-toggle {
    display: flex;
    padding: 6px;
  }
  .menu-toggle.open span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }
  .menu-toggle.open span:nth-child(2) {
    opacity: 0;
  }
  .menu-toggle.open span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }

  /* Hero Section Mobile Formatting */
  .hero-section {
    padding: calc(var(--nav-height) + 24px) 0 50px;
    text-align: center;
  }
  .tag-badge {
    font-size: 0.6875rem;
    padding: 5px 12px;
    line-height: 1.35;
    letter-spacing: 0.05em;
  }
  .hero-title {
    font-size: clamp(1.75rem, 6.6vw, 2.35rem);
    line-height: 1.36;
    margin: 16px auto 18px;
    max-width: 360px;
  }
  .hero-desc {
    font-size: 0.9375rem;
    line-height: 1.72;
    margin: 0 auto 28px;
    max-width: 340px;
  }
  .hero-cta-group {
    flex-direction: column;
    width: 100%;
    max-width: 320px;
    margin: 0 auto 32px;
    gap: 12px;
  }
  .hero-cta-group .btn {
    width: 100%;
    padding: 13px 20px;
  }
  .hero-stats {
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    padding-top: 20px;
    max-width: 360px;
    margin: 0 auto;
  }
  .stat-number {
    font-size: 1.35rem;
  }
  .stat-label {
    font-size: 0.6875rem;
    margin-top: 2px;
  }

  /* Hero Visual Mockup */
  .mockup-container {
    max-width: 310px;
  }
  .phone-mockup-frame {
    border-radius: 36px;
    padding: 8px;
  }
  .phone-screen {
    border-radius: 28px;
    padding: 18px 14px;
  }
  .mockup-word {
    font-size: 1.55rem;
  }
  .floating-badge {
    padding: 8px 12px;
    border-radius: 14px;
  }
  .floating-badge.top-left {
    left: -12px;
    top: 8%;
    transform: scale(0.88);
  }
  .floating-badge.bottom-right {
    right: -12px;
    bottom: 6%;
    transform: scale(0.88);
  }

  /* Flagship Showcase Mobile */
  .flagship-section {
    padding: 60px 0;
  }
  .flagship-card-main {
    padding: 28px 16px;
    border-radius: 24px;
  }
  .flagship-intro-grid {
    gap: 24px;
    margin-bottom: 32px;
  }
  .flagship-badge-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
  .flagship-pillars-grid {
    grid-template-columns: 1fr;
    gap: 14px;
  }
  .pillar-card {
    padding: 22px 18px;
    border-radius: 18px;
  }

  /* Simulator Mobile */
  .simulator-section {
    padding: 60px 0;
  }
  .simulator-box {
    padding: 24px 16px;
    border-radius: 24px;
    gap: 28px;
  }
  .sim-garden-stats {
    gap: 16px;
    padding: 12px 14px;
  }
  .sim-stat-val {
    font-size: 1.3rem;
  }
  .interactive-card-arena {
    padding: 24px 16px;
    border-radius: 20px;
  }
  .word-title-text {
    font-size: 1.95rem;
  }
  .sim-btn-grid {
    grid-template-columns: 1fr;
    gap: 10px;
  }
  .sim-action-btn {
    padding: 13px 16px;
    width: 100%;
  }

  /* Matrix & Values Mobile */
  .matrix-section, .values-section, .about-section {
    padding: 60px 0;
  }
  .section-header {
    margin-bottom: 36px;
  }
  .section-title {
    font-size: 1.75rem;
    line-height: 1.28;
  }
  .section-desc {
    font-size: 0.9375rem;
  }
  .matrix-grid {
    grid-template-columns: 1fr;
    gap: 18px;
  }
  .matrix-card {
    padding: 26px 20px;
    border-radius: 20px;
  }
  .values-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  .value-card {
    padding: 22px 18px;
    border-radius: 18px;
    flex-direction: column;
    gap: 14px;
  }
  .value-icon-wrapper {
    width: 48px;
    height: 48px;
    border-radius: 14px;
  }

  /* About Banner Mobile */
  .about-banner {
    padding: 30px 18px;
    border-radius: 24px;
    gap: 28px;
  }
  .about-cards-sub {
    grid-template-columns: 1fr 1fr;
    gap: 10px;
  }
  .about-mini-card {
    padding: 14px 10px;
  }
  .about-mini-card strong {
    font-size: 0.95rem;
  }

  /* Footer Mobile */
  .site-footer {
    padding: 50px 0 30px;
  }
  .footer-top-grid {
    grid-template-columns: 1fr;
    gap: 28px;
    margin-bottom: 36px;
  }
  .footer-bottom-bar {
    flex-direction: column;
    text-align: center;
    gap: 12px;
    padding-top: 20px;
  }
}

@media (max-width: 380px) {
  .hero-title {
    font-size: 1.625rem;
  }
  .brand-title {
    font-size: 0.95rem;
  }
  .brand-sub {
    display: none;
  }
  .hero-stats {
    grid-template-columns: 1fr;
    gap: 14px;
  }
}

@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;
  }
}