:root {
  /* Default Light Neomorphism */
  --bg-color: #e0e5ec;
  --card-bg: #e0e5ec;
  --primary-color: #d97706; /* 稍深的琥珀色以保证在亮色背景下的对比度 */
  --text-primary: #2d3748;
  --text-secondary: #718096;
  
  --shadow-light: rgba(255, 255, 255, 0.9);
  --shadow-dark: rgba(163, 177, 198, 0.5);
  --neu-out: -6px -6px 14px var(--shadow-light), 6px 6px 14px var(--shadow-dark);
  --neu-in: inset -4px -4px 8px var(--shadow-light), inset 4px 4px 8px var(--shadow-dark);
  --header-bg: rgba(224, 229, 236, 0.85);
  --led-off: #a3b1c6;
}

[data-theme="dark"] {
  /* Dark Neomorphism */
  --bg-color: #121114;
  --card-bg: #1a191d;
  --primary-color: #f59e0b;
  --text-primary: #e2e2e2;
  --text-secondary: #a0a0a0;
  
  --shadow-light: rgba(255, 255, 255, 0.03);
  --shadow-dark: rgba(0, 0, 0, 0.6);
  --neu-out: -5px -5px 10px var(--shadow-light), 5px 5px 12px var(--shadow-dark);
  --neu-in: inset -4px -4px 8px var(--shadow-light), inset 4px 4px 8px var(--shadow-dark);
  --header-bg: rgba(18, 17, 20, 0.85);
  --led-off: #2a2a2a;
}

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-color);
  color: var(--text-primary);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  margin: 0;
  padding: 0;
  line-height: 1.6;
  transition: background-color 0.4s ease, color 0.4s ease;
}

/* Header & Nav */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.2rem 5%;
  position: sticky;
  top: 0;
  background-color: var(--header-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 1000;
  border-bottom: 1px solid rgba(128,128,128,0.05);
  transition: background-color 0.4s ease;
}

.logo {
  font-size: 1.4rem;
  font-weight: bold;
  color: var(--primary-color);
  text-shadow: 0 0 15px rgba(245, 158, 11, 0.2);
}
.logo a { color: inherit; text-decoration: none; }

nav ul {
  display: flex;
  list-style: none;
  gap: 2rem;
  margin: 0;
  padding: 0;
}

nav a {
  color: var(--text-primary);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.3s;
}

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

/* Premium Hardware Theme Switch Button */
.theme-switch {
  width: 68px;
  height: 32px;
  border-radius: 16px;
  background: var(--card-bg);
  box-shadow: var(--neu-in);
  border: 1px solid rgba(128,128,128,0.03);
  position: relative;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 10px;
  outline: none;
  transition: all 0.4s ease;
}

.theme-switch::after {
  content: '';
  position: absolute;
  top: 3px;
  left: 4px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--card-bg);
  box-shadow: var(--neu-out);
  transition: transform 0.5s cubic-bezier(0.5, 1.5, 0.4, 1), background 0.4s ease;
  z-index: 2;
}

/* Micro LED indicator on the thumb */
.theme-switch::before {
  content: '';
  position: absolute;
  top: 13px;
  left: 14px;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: #a0a0a0;
  box-shadow: inset 1px 1px 2px rgba(0,0,0,0.3);
  z-index: 3;
  transition: transform 0.5s cubic-bezier(0.5, 1.5, 0.4, 1), background 0.4s ease, box-shadow 0.4s ease;
  pointer-events: none;
}

[data-theme="dark"] .theme-switch::after {
  transform: translateX(36px);
}

[data-theme="dark"] .theme-switch::before {
  transform: translateX(36px);
  background: var(--primary-color);
  box-shadow: 0 0 6px var(--primary-color), 0 0 10px var(--primary-color);
}

.theme-switch svg {
  width: 14px;
  height: 14px;
  fill: var(--text-secondary);
  z-index: 1;
  transition: all 0.4s ease;
}

.theme-switch .sun-icon {
  opacity: 1;
  fill: var(--primary-color);
}

.theme-switch .moon-icon {
  opacity: 0.3;
}

[data-theme="dark"] .theme-switch .sun-icon {
  opacity: 0.3;
  fill: var(--text-secondary);
}

[data-theme="dark"] .theme-switch .moon-icon {
  opacity: 1;
  fill: var(--primary-color);
  filter: drop-shadow(0 0 2px rgba(245, 158, 11, 0.5));
}


/* Neumorphic Cards */
.card {
  background: var(--card-bg);
  border-radius: 16px;
  padding: 2.5rem;
  box-shadow: var(--neu-out);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.3s cubic-bezier(0.4, 0, 0.2, 1), background 0.4s ease;
  border: 1px solid rgba(128,128,128,0.02);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: -8px -8px 16px var(--shadow-light), 8px 8px 16px var(--shadow-dark), 0 0 20px rgba(245, 158, 11, 0.08);
}

/* Buttons */
.btn {
  display: inline-block;
  background: var(--card-bg);
  color: var(--primary-color) !important;
  padding: 0.8rem 2rem;
  border-radius: 8px;
  font-weight: bold;
  text-align: center;
  text-decoration: none;
  box-shadow: var(--neu-out);
  transition: all 0.2s ease;
  border: 1px solid rgba(128,128,128,0.02);
}

.btn:hover {
  color: var(--primary-color) !important;
  text-shadow: none;
}

[data-theme="dark"] .btn:hover {
  color: #fff !important;
  text-shadow: 0 0 8px rgba(245, 158, 11, 0.5);
}

.btn:active, .btn-active {
  box-shadow: var(--neu-in);
  color: var(--primary-color) !important;
  transform: scale(0.98);
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 7rem 5% 5rem;
}

.hero h1 {
  font-size: 3.2rem;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
  letter-spacing: 1px;
}

.hero p {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 3.5rem;
  max-width: 800px;
  margin-inline: auto;
}

/* Interactive Toggle */
.toggle-wrapper {
  margin: 3rem 0 2rem;
}

.toggle-btn {
  background: var(--card-bg);
  width: 240px;
  height: 64px;
  border-radius: 32px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--neu-out);
  cursor: pointer;
  user-select: none;
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  border: 1px solid rgba(128,128,128,0.02);
  font-weight: bold;
  color: var(--text-secondary);
  gap: 12px;
  font-size: 1.05rem;
}

.toggle-btn.active {
  box-shadow: var(--neu-in);
  color: var(--primary-color);
}

.led {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--led-off);
  box-shadow: inset 2px 2px 4px rgba(0,0,0,0.1);
  transition: all 0.4s ease;
}

[data-theme="dark"] .led {
  box-shadow: inset 2px 2px 4px rgba(0,0,0,0.5);
}

.toggle-btn.active .led {
  background: var(--primary-color);
  box-shadow: 0 0 12px var(--primary-color), 0 0 25px var(--primary-color), inset -2px -2px 4px rgba(0,0,0,0.2);
}

/* Layout */
section {
  padding: 5rem 5%;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2.5rem;
}

/* Sections details */
.section-title {
  text-align: center;
  margin-bottom: 4rem;
  font-size: 2.2rem;
  color: var(--text-primary);
}

.price {
  font-size: 2.5rem;
  font-weight: bold;
  color: var(--primary-color);
  margin: 1.5rem 0;
}

[data-theme="dark"] .price {
  text-shadow: 0 0 20px rgba(245, 158, 11, 0.15);
}

.pricing .card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.pricing h3 {
  color: var(--text-primary);
}

/* FAQ */
.faq-item {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 2rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--neu-out);
  border: 1px solid rgba(128,128,128,0.015);
  transition: all 0.4s ease;
}

.faq-item h4 {
  color: var(--primary-color);
  margin-bottom: 0.8rem;
  font-size: 1.1rem;
}

/* Sub-pages specific */
.page-content {
  max-width: 800px;
  margin: 0 auto;
}
.page-content h3 {
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}
.page-content p {
  color: var(--text-secondary);
}

/* Footer */
footer {
  text-align: center;
  padding: 4rem 5% 3rem;
  margin-top: 2rem;
  border-top: 1px solid rgba(128,128,128,0.05);
}

footer a {
  color: var(--text-secondary);
  margin: 0 1.2rem;
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.3s;
}
footer a:hover {
  color: var(--primary-color);
}

@media (max-width: 768px) {
  nav { display: none; }
  .hero h1 { font-size: 2.2rem; }
  .toggle-btn { width: 100%; max-width: 280px; }
  .section-title { font-size: 1.8rem; margin-bottom: 2.5rem; }
  header .btn { display: none; }
  .header-actions { gap: 0.5rem; }
  footer a { display: block; margin: 1rem 0; }
}