/* ==========================================================================
   iKuuu VPN (ikuuuvpn.cyou) - Cryogenic Icy-Mint Minimalist UI System
   Palette:
     Glacier White:      #f8fafc
     Cryogenic Mint Cyan: #00f5d4 / #05d5b7
     Sub-Zero Cobalt:    #0284c7 / #0369a1
     Polar Navy:         #0f172a / #030712
   Floating Ice-Slab Architecture | Zero generic bot icons | Pure Native CSS
   ========================================================================== */

:root {
  /* Cryogenic Light Mode (Default) */
  --ice-bg: #f8fafc;
  --ice-bg-gradient: radial-gradient(circle at 50% 0%, #e0f2fe 0%, #f0fdfa 40%, #f8fafc 80%);
  --sky-gradient: linear-gradient(180deg, #e0f2fe 0%, #f8fafc 100%);
  
  --ice-slab: rgba(255, 255, 255, 0.72);
  --ice-slab-hover: rgba(255, 255, 255, 0.92);
  --ice-slab-active: rgba(240, 253, 250, 0.95);
  --ice-border: rgba(255, 255, 255, 0.9);
  --ice-border-subtle: rgba(2, 132, 199, 0.12);
  --ice-bevel: inset 0 1px 1px 0 rgba(255, 255, 255, 0.95), inset 0 -1px 1px 0 rgba(2, 132, 199, 0.08);
  
  --mint-cyan: #00f5d4;
  --mint-cyan-glow: rgba(0, 245, 212, 0.45);
  --mint-dark: #0d9488;
  --mint-tint: rgba(0, 245, 212, 0.12);
  
  --cobalt-blue: #0284c7;
  --cobalt-deep: #0369a1;
  --cobalt-glow: rgba(2, 132, 199, 0.28);
  --cobalt-tint: rgba(2, 132, 199, 0.08);

  --polar-navy: #0f172a;
  --polar-slate: #334155;
  --polar-muted: #64748b;

  --frost-header: rgba(248, 250, 252, 0.82);
  --frost-blur: blur(20px) saturate(180%);
  
  --shadow-ice-sm: 0 4px 12px -2px rgba(2, 132, 199, 0.08), 0 2px 6px -1px rgba(0, 245, 212, 0.05);
  --shadow-ice-md: 0 12px 28px -6px rgba(2, 132, 199, 0.12), 0 6px 14px -3px rgba(0, 245, 212, 0.08);
  --shadow-ice-lg: 0 24px 48px -10px rgba(2, 132, 199, 0.16), 0 12px 24px -5px rgba(0, 245, 212, 0.1);
  --shadow-caustic: 0 0 40px rgba(0, 245, 212, 0.35);

  --transition-liquid: cubic-bezier(0.16, 1, 0.3, 1);
  --radius-ice-sm: 10px;
  --radius-ice-md: 16px;
  --radius-ice-lg: 24px;
  --radius-ice-xl: 32px;
  --radius-pill: 9999px;
  --container-max: 1340px;
}

[data-theme="dark"] {
  /* Cryogenic Polar Midnight Mode */
  --ice-bg: #060b14;
  --ice-bg-gradient: radial-gradient(circle at 50% 0%, #0d1e38 0%, #061324 45%, #060b14 85%);
  --sky-gradient: linear-gradient(180deg, #0d1e38 0%, #060b14 100%);
  
  --ice-slab: rgba(14, 25, 45, 0.65);
  --ice-slab-hover: rgba(20, 36, 64, 0.82);
  --ice-slab-active: rgba(18, 38, 70, 0.9);
  --ice-border: rgba(0, 245, 212, 0.22);
  --ice-border-subtle: rgba(2, 132, 199, 0.25);
  --ice-bevel: inset 0 1px 1px 0 rgba(255, 255, 255, 0.15), inset 0 -1px 1px 0 rgba(0, 0, 0, 0.4);
  
  --mint-cyan: #00f5d4;
  --mint-cyan-glow: rgba(0, 245, 212, 0.6);
  --mint-dark: #2dd4bf;
  --mint-tint: rgba(0, 245, 212, 0.16);
  
  --cobalt-blue: #38bdf8;
  --cobalt-deep: #0284c7;
  --cobalt-glow: rgba(56, 189, 248, 0.35);
  --cobalt-tint: rgba(56, 189, 248, 0.12);

  --polar-navy: #f8fafc;
  --polar-slate: #cbd5e1;
  --polar-muted: #94a3b8;

  --frost-header: rgba(6, 11, 20, 0.85);
  
  --shadow-ice-sm: 0 4px 14px rgba(0, 0, 0, 0.5);
  --shadow-ice-md: 0 12px 30px rgba(0, 0, 0, 0.65), 0 0 20px rgba(0, 245, 212, 0.15);
  --shadow-ice-lg: 0 24px 50px rgba(0, 0, 0, 0.8), 0 0 35px rgba(2, 132, 199, 0.25);
  --shadow-caustic: 0 0 45px rgba(0, 245, 212, 0.45);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 86px;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: var(--ice-bg);
  background-image: var(--ice-bg-gradient);
  background-attachment: fixed;
  color: var(--polar-navy);
  line-height: 1.68;
  transition: background var(--transition-liquid) 0.35s, color var(--transition-liquid) 0.35s;
  overflow-x: hidden;
  position: relative;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
  transition: all 0.22s var(--transition-liquid);
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  transition: all 0.22s var(--transition-liquid);
}

ul, ol {
  list-style: none;
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 28px;
  padding-right: 28px;
}

/* Font Monospace for ping and numbers */
.font-mono {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
}

/* ==========================================================================
   Header & Floating Frosted Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--frost-header);
  backdrop-filter: var(--frost-blur);
  -webkit-backdrop-filter: var(--frost-blur);
  border-bottom: 1px solid var(--ice-border-subtle);
  box-shadow: 0 4px 20px rgba(2, 132, 199, 0.04);
  transition: all 0.3s var(--transition-liquid);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
  gap: 16px;
}

/* Brand Logo */
.brand-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.34rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--polar-navy);
  white-space: nowrap;
  flex-shrink: 0;
}

.brand-logo-img {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  object-fit: cover;
  display: block;
  box-shadow: 0 2px 10px rgba(2, 132, 199, 0.25), 0 0 14px rgba(0, 245, 212, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.85);
  transition: transform 0.3s var(--transition-liquid), box-shadow 0.3s ease;
  flex-shrink: 0;
}

.brand-logo:hover .brand-logo-img {
  transform: scale(1.08) rotate(5deg);
  box-shadow: 0 4px 16px rgba(0, 245, 212, 0.55);
}

.crystal-logo-mark {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-ice-sm);
  background: linear-gradient(135deg, var(--mint-cyan) 0%, var(--cobalt-blue) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #04101e;
  box-shadow: 0 4px 16px var(--mint-cyan-glow), var(--ice-bevel);
  position: relative;
  overflow: hidden;
  flex-shrink: 0;
}

.crystal-logo-mark::after {
  content: "";
  position: absolute;
  top: 0;
  left: -50%;
  width: 200%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.4), transparent);
  transform: skewX(-20deg);
  animation: crystalShimmer 4s infinite;
}

@keyframes crystalShimmer {
  0% { transform: translateX(-150%) skewX(-20deg); }
  35%, 100% { transform: translateX(150%) skewX(-20deg); }
}

.brand-logo-text {
  white-space: nowrap;
  display: inline-block;
  background: linear-gradient(135deg, var(--polar-navy) 40%, var(--cobalt-blue) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

[data-theme="dark"] .brand-logo-text {
  background: linear-gradient(135deg, #ffffff 40%, var(--mint-cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand-domain-pill {
  font-size: 0.74rem;
  font-weight: 700;
  color: var(--mint-dark);
  background: var(--mint-tint);
  border: 1px solid rgba(0, 245, 212, 0.35);
  padding: 2px 8px;
  border-radius: var(--radius-pill);
  white-space: nowrap;
  flex-shrink: 0;
}

/* Nav Menu */
.nav-menu {
  display: flex;
  align-items: center;
  gap: clamp(6px, 1.1vw, 16px);
  white-space: nowrap;
  flex-shrink: 1;
}

.nav-link {
  font-size: clamp(0.86rem, 0.95vw, 0.93rem);
  font-weight: 600;
  color: var(--polar-slate);
  position: relative;
  padding: 6px 10px;
  border-radius: var(--radius-pill);
  transition: all 0.25s var(--transition-liquid);
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  line-height: 1.4;
}

.nav-link:hover {
  color: var(--cobalt-blue);
  background: var(--cobalt-tint);
}

.nav-link.active {
  color: var(--cobalt-blue);
  background: var(--cobalt-tint);
}

/* Special "推荐资讯" Nav Link Highlight */
.nav-link-special {
  color: var(--mint-dark);
  background: var(--mint-tint);
  border: 1px solid rgba(0, 245, 212, 0.4);
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  white-space: nowrap;
  flex-shrink: 0;
}

.nav-link-special:hover {
  background: var(--mint-cyan);
  color: #04101e;
  box-shadow: 0 2px 10px var(--mint-cyan-glow);
  border-color: var(--mint-cyan);
}

.nav-link-special .spark-icon {
  width: 14px;
  height: 14px;
  color: inherit;
  flex-shrink: 0;
}

/* Header Actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  white-space: nowrap;
  flex-shrink: 0;
}

/* Day / Night Mode Switcher (Frosted Crystal Button) */
.theme-toggle-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--ice-slab);
  backdrop-filter: var(--frost-blur);
  border: 1px solid var(--ice-border);
  box-shadow: var(--ice-bevel), var(--shadow-ice-sm);
  color: var(--polar-navy);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  transition: all 0.3s var(--transition-liquid);
}

.theme-toggle-btn:hover {
  background: var(--ice-slab-hover);
  border-color: var(--mint-cyan);
  transform: translateY(-2px) scale(1.05);
  box-shadow: 0 4px 18px var(--mint-cyan-glow);
}

.theme-icon {
  width: 20px;
  height: 20px;
  position: absolute;
  transition: transform 0.45s var(--transition-liquid), opacity 0.3s ease;
}

.theme-icon.sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
  color: #0284c7;
}

.theme-icon.moon {
  opacity: 0;
  transform: rotate(90deg) scale(0.4);
  color: var(--mint-cyan);
}

[data-theme="dark"] .theme-icon.sun {
  opacity: 0;
  transform: rotate(-90deg) scale(0.4);
}

[data-theme="dark"] .theme-icon.moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.mobile-menu-btn {
  display: none;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-ice-sm);
  background: var(--ice-slab);
  border: 1px solid var(--ice-border);
  color: var(--polar-navy);
  align-items: center;
  justify-content: center;
}

/* ==========================================================================
   Buttons (Bevel-Cut Ice Quartz & Cryogenic Mint)
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 700;
  border-radius: var(--radius-pill);
  transition: all 0.25s var(--transition-liquid);
  white-space: nowrap;
  user-select: none;
  position: relative;
  overflow: hidden;
}

.btn-sm {
  padding: 8px 20px;
  font-size: 0.88rem;
}

.btn-md {
  padding: 12px 28px;
  font-size: 0.98rem;
}

.btn-lg {
  padding: 16px 36px;
  font-size: 1.05rem;
}

/* Cryogenic Mint Primary Button */
.btn-primary {
  background: linear-gradient(135deg, #00f5d4 0%, #0284c7 100%);
  color: #031525;
  box-shadow: 0 6px 24px rgba(0, 245, 212, 0.42), var(--ice-bevel);
  border: 1px solid rgba(255, 255, 255, 0.6);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 32px rgba(0, 245, 212, 0.6), var(--ice-bevel);
  color: #010a12;
}

/* Ice-Quartz Frosted Secondary Button */
.btn-secondary {
  background: var(--ice-slab);
  backdrop-filter: var(--frost-blur);
  border: 1px solid var(--ice-border);
  box-shadow: var(--ice-bevel), var(--shadow-ice-sm);
  color: var(--polar-navy);
}

.btn-secondary:hover {
  background: var(--ice-slab-hover);
  border-color: var(--cobalt-blue);
  transform: translateY(-2px);
  box-shadow: var(--shadow-ice-md);
  color: var(--cobalt-blue);
}

/* ==========================================================================
   Floating Ice-Slab Containers (Architecture)
   ========================================================================== */
.ice-slab-card {
  background: var(--ice-slab);
  backdrop-filter: var(--frost-blur);
  -webkit-backdrop-filter: var(--frost-blur);
  border: 1px solid var(--ice-border);
  border-radius: var(--radius-ice-lg);
  box-shadow: var(--ice-bevel), var(--shadow-ice-md);
  transition: all 0.35s var(--transition-liquid);
  position: relative;
}

.ice-slab-card:hover {
  background: var(--ice-slab-hover);
  border-color: rgba(0, 245, 212, 0.45);
  box-shadow: var(--ice-bevel), var(--shadow-ice-lg), 0 0 24px rgba(0, 245, 212, 0.18);
  transform: translateY(-4px);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section {
  padding: 72px 0 56px;
  position: relative;
  text-align: center;
}

.hero-aurora-pill {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 22px;
  border-radius: var(--radius-pill);
  background: var(--ice-slab);
  backdrop-filter: var(--frost-blur);
  border: 1px solid var(--ice-border);
  box-shadow: var(--ice-bevel), 0 2px 12px rgba(0, 245, 212, 0.2);
  color: var(--polar-navy);
  font-size: 0.9rem;
  font-weight: 700;
  margin-bottom: 24px;
}

.crystal-pulse-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background-color: var(--mint-cyan);
  box-shadow: 0 0 12px var(--mint-cyan);
  animation: pulseCyan 2s infinite;
}

@keyframes pulseCyan {
  0% { box-shadow: 0 0 0 0 rgba(0, 245, 212, 0.7); }
  70% { box-shadow: 0 0 0 10px rgba(0, 245, 212, 0); }
  100% { box-shadow: 0 0 0 0 rgba(0, 245, 212, 0); }
}

.hero-title {
  font-size: clamp(2.3rem, 5.2vw, 3.9rem);
  font-weight: 900;
  letter-spacing: -0.035em;
  line-height: 1.14;
  margin-bottom: 22px;
  color: var(--polar-navy);
}

.brand-gradient-title {
  background: linear-gradient(135deg, var(--cobalt-blue) 0%, var(--mint-cyan) 60%, var(--cobalt-deep) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
  padding-right: 4px;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--polar-slate);
  max-width: 820px;
  margin: 0 auto 36px;
  line-height: 1.75;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
  margin-bottom: 52px;
}

/* ==========================================================================
   Central "Daily Check-in / Free Bandwidth" Module (Ice-Caustic Interactive)
   ========================================================================== */
.checkin-slab-wrapper {
  max-width: 860px;
  margin: 0 auto 72px;
}

.checkin-crystal-container {
  background: var(--ice-slab);
  backdrop-filter: var(--frost-blur);
  -webkit-backdrop-filter: var(--frost-blur);
  border: 1px solid var(--ice-border);
  border-radius: var(--radius-ice-xl);
  padding: 38px 40px;
  box-shadow: var(--ice-bevel), var(--shadow-ice-lg);
  position: relative;
  overflow: hidden;
  transition: all 0.35s var(--transition-liquid);
}

/* Dynamic Caustic Refractive Sheen */
.caustic-sheen {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  background: radial-gradient(circle 350px at var(--mouse-x, 50%) var(--mouse-y, 30%), rgba(0, 245, 212, 0.22) 0%, rgba(2, 132, 199, 0.1) 45%, transparent 75%);
  opacity: 0.9;
  transition: opacity 0.3s;
}

.checkin-header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.checkin-title-box {
  text-align: left;
}

.checkin-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--mint-dark);
  background: var(--mint-tint);
  border: 1px solid rgba(0, 245, 212, 0.3);
  padding: 3px 10px;
  border-radius: var(--radius-pill);
  margin-bottom: 6px;
}

.checkin-title {
  font-size: 1.42rem;
  font-weight: 800;
  color: var(--polar-navy);
}

/* Fluid Meter Progress Bar Physics */
.quota-meter-wrapper {
  margin: 24px 0 28px;
}

.quota-meter-meta {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 10px;
  font-size: 0.92rem;
}

.quota-label {
  font-weight: 600;
  color: var(--polar-slate);
}

.quota-value {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--cobalt-blue);
}

[data-theme="dark"] .quota-value {
  color: var(--mint-cyan);
}

.quota-bar-track {
  width: 100%;
  height: 16px;
  background: rgba(2, 132, 199, 0.08);
  border: 1px solid var(--ice-border-subtle);
  border-radius: var(--radius-pill);
  position: relative;
  overflow: hidden;
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.06);
}

.quota-bar-fill {
  width: 50%;
  height: 100%;
  border-radius: var(--radius-pill);
  background: linear-gradient(90deg, var(--cobalt-blue) 0%, var(--mint-cyan) 100%);
  box-shadow: 0 0 16px var(--mint-cyan-glow);
  position: relative;
  transition: width 0.95s var(--transition-liquid);
}

.quota-bar-fill::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(90deg, transparent 0%, rgba(255, 255, 255, 0.6) 50%, transparent 100%);
  animation: fluidWave 2.8s infinite;
}

@keyframes fluidWave {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

/* Monospace Ping Live Meters */
.ping-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-bottom: 26px;
}

.ping-node-item {
  background: var(--ice-slab);
  border: 1px solid var(--ice-border-subtle);
  border-radius: var(--radius-ice-sm);
  padding: 10px 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
}

.ping-node-name {
  font-weight: 600;
  color: var(--polar-navy);
  display: flex;
  align-items: center;
  gap: 6px;
}

.ping-value {
  font-weight: 700;
  color: #10b981;
}

/* Checkin Trigger Button with Crystalline Fracture Animation */
.checkin-btn-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn-crystal-checkin {
  padding: 14px 34px;
  font-size: 1.02rem;
  font-weight: 800;
  color: #031422;
  background: linear-gradient(135deg, #00f5d4 0%, #38bdf8 100%);
  border-radius: var(--radius-pill);
  box-shadow: 0 6px 25px var(--mint-cyan-glow), var(--ice-bevel);
  border: 1px solid rgba(255, 255, 255, 0.7);
  position: relative;
  overflow: hidden;
}

.btn-crystal-checkin:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 10px 32px var(--mint-cyan-glow);
}

.btn-crystal-checkin:disabled {
  background: var(--ice-slab);
  color: var(--polar-muted);
  border-color: var(--ice-border-subtle);
  box-shadow: none;
  cursor: not-allowed;
}

/* Fracture animation burst */
.fracture-spark {
  position: absolute;
  pointer-events: none;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--mint-cyan);
  box-shadow: 0 0 10px var(--mint-cyan);
  animation: sparkBurst 0.7s forwards ease-out;
}

@keyframes sparkBurst {
  0% { transform: translate(0, 0) scale(1); opacity: 1; }
  100% { transform: translate(var(--tx), var(--ty)) scale(0); opacity: 0; }
}

.checkin-toast {
  display: none;
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--mint-dark);
  background: var(--mint-tint);
  border: 1px solid var(--mint-cyan);
  padding: 8px 18px;
  border-radius: var(--radius-pill);
  animation: fadeIn 0.4s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ==========================================================================
   Section Headers
   ========================================================================== */
.section-block {
  padding: 64px 0;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 52px;
}

.section-pill-tag {
  display: inline-block;
  padding: 5px 16px;
  background: var(--mint-tint);
  border: 1px solid rgba(0, 245, 212, 0.35);
  color: var(--mint-dark);
  font-size: 0.82rem;
  font-weight: 700;
  border-radius: var(--radius-pill);
  margin-bottom: 14px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.section-title {
  font-size: clamp(1.9rem, 3.8vw, 2.6rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  margin-bottom: 16px;
  color: var(--polar-navy);
}

.section-subtitle {
  font-size: 1.06rem;
  color: var(--polar-slate);
  line-height: 1.7;
}

/* ==========================================================================
   Core Advantages (3 Graphic Cards)
   ========================================================================== */
.core-features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.feature-crystal-card {
  padding: 34px 30px;
  display: flex;
  flex-direction: column;
}

.feature-icon-prism {
  width: 58px;
  height: 58px;
  border-radius: var(--radius-ice-md);
  background: linear-gradient(135deg, var(--mint-tint) 0%, var(--cobalt-tint) 100%);
  border: 1px solid rgba(0, 245, 212, 0.35);
  box-shadow: var(--ice-bevel);
  color: var(--cobalt-blue);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
  transition: transform 0.35s var(--transition-liquid);
}

[data-theme="dark"] .feature-icon-prism {
  color: var(--mint-cyan);
}

.feature-crystal-card:hover .feature-icon-prism {
  transform: rotate(6deg) scale(1.1);
  box-shadow: 0 0 20px var(--mint-cyan-glow);
}

.feature-title {
  font-size: 1.36rem;
  font-weight: 800;
  margin-bottom: 12px;
  color: var(--polar-navy);
}

.feature-desc {
  font-size: 0.95rem;
  color: var(--polar-slate);
  line-height: 1.68;
  margin-bottom: 20px;
  flex-grow: 1;
}

.feature-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.mini-frost-pill {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--polar-muted);
  background: rgba(2, 132, 199, 0.06);
  border: 1px solid var(--ice-border-subtle);
  padding: 3px 10px;
  border-radius: var(--radius-pill);
}

/* ==========================================================================
   Streaming Card & AI Support Card (流媒体图卡 + AI支持图卡)
   ========================================================================== */
.showcase-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.showcase-crystal-card {
  padding: 38px 34px;
  display: flex;
  flex-direction: column;
}

.showcase-badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 4px 14px;
  border-radius: var(--radius-pill);
  margin-bottom: 18px;
  width: fit-content;
}

.showcase-badge-pill.stream {
  background: rgba(239, 68, 68, 0.1);
  color: #ef4444;
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.showcase-badge-pill.ai {
  background: var(--mint-tint);
  color: var(--mint-dark);
  border: 1px solid rgba(0, 245, 212, 0.4);
}

.showcase-title {
  font-size: 1.58rem;
  font-weight: 800;
  margin-bottom: 12px;
  color: var(--polar-navy);
}

.showcase-desc {
  font-size: 0.96rem;
  color: var(--polar-slate);
  line-height: 1.65;
  margin-bottom: 24px;
}

.matrix-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 26px;
}

.matrix-item {
  background: var(--ice-slab);
  border: 1px solid var(--ice-border-subtle);
  border-radius: var(--radius-ice-sm);
  padding: 12px 10px;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 5px;
  transition: all 0.25s var(--transition-liquid);
}

.matrix-item:hover {
  border-color: var(--mint-cyan);
  transform: translateY(-2px);
  box-shadow: 0 4px 14px var(--mint-cyan-glow);
}

.matrix-name {
  font-size: 0.86rem;
  font-weight: 700;
  color: var(--polar-navy);
}

.matrix-status {
  font-size: 0.73rem;
  font-weight: 700;
  color: #10b981;
}

.bullet-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 28px;
}

.bullet-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.92rem;
  color: var(--polar-slate);
}

.bullet-item svg {
  color: var(--cobalt-blue);
  flex-shrink: 0;
}

[data-theme="dark"] .bullet-item svg {
  color: var(--mint-cyan);
}

/* ==========================================================================
   Pricing Table (参考真实套餐：免费版 + 月付¥12 + 季付¥30 + 年付¥108)
   ========================================================================== */
.pricing-grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
  align-items: stretch;
}

.pricing-card {
  padding: 34px 26px;
  display: flex;
  flex-direction: column;
  position: relative;
}

.pricing-card.featured {
  border: 2px solid var(--mint-cyan);
  box-shadow: var(--ice-bevel), var(--shadow-ice-lg), 0 0 32px var(--mint-cyan-glow);
  transform: scale(1.025);
  z-index: 2;
}

.pricing-card.featured:hover {
  transform: scale(1.025) translateY(-5px);
}

.pricing-ribbon {
  position: absolute;
  top: -13px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, #00f5d4 0%, #0284c7 100%);
  color: #031525;
  font-size: 0.78rem;
  font-weight: 800;
  padding: 3px 16px;
  border-radius: var(--radius-pill);
  box-shadow: 0 4px 14px var(--mint-cyan-glow);
  white-space: nowrap;
}

.pricing-title {
  font-size: 1.3rem;
  font-weight: 800;
  margin-bottom: 6px;
  color: var(--polar-navy);
}

.pricing-sub {
  font-size: 0.84rem;
  color: var(--polar-muted);
  min-height: 40px;
}

.pricing-amount-box {
  margin: 18px 0;
  text-align: center;
}

.pricing-currency {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--cobalt-blue);
  vertical-align: super;
}

[data-theme="dark"] .pricing-currency {
  color: var(--mint-cyan);
}

.pricing-num {
  font-size: 2.8rem;
  font-weight: 900;
  line-height: 1;
  color: var(--polar-navy);
}

.pricing-cycle {
  font-size: 0.86rem;
  color: var(--polar-muted);
  font-weight: 500;
}

.pricing-traffic-tag {
  display: inline-block;
  padding: 4px 12px;
  background: var(--cobalt-tint);
  border: 1px solid var(--ice-border-subtle);
  color: var(--cobalt-blue);
  font-size: 0.84rem;
  font-weight: 800;
  border-radius: var(--radius-pill);
}

[data-theme="dark"] .pricing-traffic-tag {
  color: var(--mint-cyan);
  background: var(--mint-tint);
}

.pricing-features {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 24px 0;
  flex-grow: 1;
}

.pricing-feature-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--polar-slate);
}

.pricing-feature-row svg {
  flex-shrink: 0;
  color: #10b981;
}

.pricing-feature-row.disabled {
  color: var(--polar-muted);
  opacity: 0.5;
}

.pricing-feature-row.disabled svg {
  color: var(--polar-muted);
}

.pricing-btn-wrap {
  margin-top: auto;
}

.pricing-btn-wrap .btn {
  width: 100%;
}

/* ==========================================================================
   Testimonials (用户评价)
   ========================================================================== */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.testimonial-crystal-card {
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.stars-rating {
  color: #f59e0b;
  display: flex;
  gap: 3px;
  margin-bottom: 14px;
}

.testimonial-text {
  font-size: 0.95rem;
  color: var(--polar-slate);
  line-height: 1.7;
  margin-bottom: 22px;
}

.author-block {
  display: flex;
  align-items: center;
  gap: 12px;
}

.author-crystal-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--mint-cyan) 0%, var(--cobalt-blue) 100%);
  color: #031422;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
}

.author-name {
  font-size: 0.96rem;
  font-weight: 800;
  color: var(--polar-navy);
}

.author-role {
  font-size: 0.8rem;
  color: var(--polar-muted);
}

/* ==========================================================================
   FAQ Accordion
   ========================================================================== */
.faq-box {
  max-width: 860px;
  margin: 0 auto;
}

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-crystal-item {
  background: var(--ice-slab);
  border: 1px solid var(--ice-border);
  border-radius: var(--radius-ice-md);
  box-shadow: var(--ice-bevel), var(--shadow-ice-sm);
  overflow: hidden;
  transition: all 0.3s var(--transition-liquid);
}

.faq-crystal-item:hover {
  border-color: rgba(0, 245, 212, 0.5);
}

.faq-trigger {
  width: 100%;
  text-align: left;
  padding: 22px 26px;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--polar-navy);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  cursor: pointer;
}

.faq-arrow-icon {
  width: 20px;
  height: 20px;
  color: var(--cobalt-blue);
  transition: transform 0.35s var(--transition-liquid);
  flex-shrink: 0;
}

[data-theme="dark"] .faq-arrow-icon {
  color: var(--mint-cyan);
}

.faq-crystal-item.active .faq-arrow-icon {
  transform: rotate(180deg);
}

.faq-panel {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s var(--transition-liquid);
  background: rgba(2, 132, 199, 0.03);
}

.faq-crystal-item.active .faq-panel {
  max-height: 400px;
  border-top: 1px solid var(--ice-border-subtle);
}

.faq-content-inner {
  padding: 22px 26px;
  font-size: 0.95rem;
  color: var(--polar-slate);
  line-height: 1.75;
}

/* ==========================================================================
   Bottom CTA Hero Banner
   ========================================================================== */
.bottom-cta-slab {
  background: linear-gradient(135deg, rgba(0, 245, 212, 0.15) 0%, rgba(2, 132, 199, 0.25) 100%), var(--ice-slab);
  backdrop-filter: var(--frost-blur);
  border: 1px solid rgba(0, 245, 212, 0.4);
  border-radius: var(--radius-ice-xl);
  padding: 56px 36px;
  text-align: center;
  box-shadow: var(--ice-bevel), var(--shadow-ice-lg), 0 0 35px var(--mint-cyan-glow);
  position: relative;
  overflow: hidden;
}

/* ==========================================================================
   Footer (Strictly 4 Navigation Titles opening in new tab + Copyright)
   ========================================================================== */
.site-footer {
  border-top: 1px solid var(--ice-border-subtle);
  background: var(--frost-header);
  backdrop-filter: var(--frost-blur);
  padding: 52px 0 38px;
  margin-top: 72px;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 28px;
  text-align: center;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
}

.footer-link {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--polar-slate);
  transition: all 0.25s var(--transition-liquid);
  position: relative;
}

.footer-link:hover {
  color: var(--cobalt-blue);
  text-decoration: underline;
  text-underline-offset: 6px;
}

[data-theme="dark"] .footer-link:hover {
  color: var(--mint-cyan);
}

.footer-copyright {
  font-size: 0.88rem;
  color: var(--polar-muted);
}

.footer-copyright a {
  color: var(--polar-muted);
}

.footer-copyright a:hover {
  color: var(--cobalt-blue);
}

/* ==========================================================================
   "推荐资讯" Blog / Article Hub (Random Name HTML page)
   ========================================================================== */
.article-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
  margin-top: 36px;
}

.article-crystal-card {
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
}

.article-meta-row {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.82rem;
  color: var(--polar-muted);
  margin-bottom: 14px;
}

.article-tag {
  background: var(--mint-tint);
  color: var(--mint-dark);
  font-weight: 700;
  padding: 2px 10px;
  border-radius: var(--radius-pill);
}

.article-title {
  font-size: 1.28rem;
  font-weight: 800;
  line-height: 1.4;
  margin-bottom: 12px;
  color: var(--polar-navy);
}

.article-title:hover {
  color: var(--cobalt-blue);
}

.article-excerpt {
  font-size: 0.94rem;
  color: var(--polar-slate);
  line-height: 1.68;
  margin-bottom: 20px;
  flex-grow: 1;
}

.article-footer-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  border-top: 1px solid var(--ice-border-subtle);
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--cobalt-blue);
}

/* Breadcrumb */
.breadcrumb-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.86rem;
  color: var(--polar-muted);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.breadcrumb-nav a {
  color: var(--polar-slate);
}

.breadcrumb-nav a:hover {
  color: var(--cobalt-blue);
}

.breadcrumb-sep {
  color: var(--polar-muted);
  opacity: 0.6;
}

/* Article Detail Layout */
.article-detail-container {
  max-width: 920px;
  margin: 0 auto;
}

.article-header-block {
  margin-bottom: 36px;
  text-align: left;
}

.article-main-title {
  font-size: clamp(1.85rem, 3.6vw, 2.6rem);
  font-weight: 900;
  line-height: 1.28;
  letter-spacing: -0.025em;
  color: var(--polar-navy);
  margin: 14px 0 18px;
}

.article-author-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 0.88rem;
  color: var(--polar-muted);
  flex-wrap: wrap;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--ice-border-subtle);
}

/* Table of Contents (TOC) */
.article-toc {
  background: var(--ice-slab);
  border: 1px solid var(--ice-border);
  border-radius: var(--radius-ice-md);
  padding: 24px 28px;
  margin: 32px 0 40px;
  box-shadow: var(--ice-bevel), var(--shadow-ice-sm);
}

.toc-heading {
  font-size: 1.12rem;
  font-weight: 800;
  color: var(--polar-navy);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-left: 6px;
}

.toc-item a {
  font-size: 0.94rem;
  font-weight: 600;
  color: var(--cobalt-blue);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.toc-item a:hover {
  color: var(--mint-dark);
  text-decoration: underline;
  text-underline-offset: 4px;
}

/* Article Body Typography */
.article-body {
  font-size: 1.05rem;
  line-height: 1.85;
  color: var(--polar-slate);
}

.article-body h2 {
  font-size: clamp(1.45rem, 2.5vw, 1.85rem);
  font-weight: 800;
  color: var(--polar-navy);
  margin: 44px 0 18px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--ice-border-subtle);
  position: relative;
}

.article-body h2::before {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 50px;
  height: 2px;
  background: var(--mint-cyan);
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--polar-navy);
  margin: 28px 0 14px;
}

.article-body p {
  margin-bottom: 20px;
}

.article-body ul, .article-body ol {
  margin: 16px 0 24px;
  padding-left: 24px;
}

.article-body ul {
  list-style: disc;
}

.article-body ol {
  list-style: decimal;
}

.article-body li {
  margin-bottom: 10px;
  line-height: 1.75;
}

.article-body strong {
  color: var(--polar-navy);
  font-weight: 700;
}

.article-body a {
  color: var(--cobalt-blue);
  text-decoration: underline;
  text-underline-offset: 4px;
  font-weight: 600;
}

.article-body a:hover {
  color: var(--mint-dark);
}

/* Info Callout */
.info-callout {
  background: var(--mint-tint);
  border-left: 4px solid var(--mint-cyan);
  border-radius: var(--radius-ice-sm);
  padding: 18px 22px;
  margin: 26px 0;
  color: var(--polar-slate);
}

.info-callout strong {
  color: var(--polar-navy);
}

.warning-callout {
  background: rgba(239, 68, 68, 0.08);
  border-left: 4px solid #ef4444;
  border-radius: var(--radius-ice-sm);
  padding: 18px 22px;
  margin: 26px 0;
  color: var(--polar-slate);
}

/* Article Comparison Table */
.article-table-wrap {
  width: 100%;
  overflow-x: auto;
  margin: 28px 0;
  border-radius: var(--radius-ice-md);
  border: 1px solid var(--ice-border);
  box-shadow: var(--ice-bevel);
}

.article-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.92rem;
  background: var(--ice-slab);
}

.article-table th {
  background: rgba(2, 132, 199, 0.08);
  color: var(--polar-navy);
  font-weight: 800;
  padding: 14px 16px;
  border-bottom: 1px solid var(--ice-border);
  white-space: nowrap;
}

.article-table td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--ice-border-subtle);
  color: var(--polar-slate);
}

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

/* Article FAQ Block */
.article-faq-section {
  margin: 48px 0;
  background: var(--ice-slab);
  border: 1px solid var(--ice-border);
  border-radius: var(--radius-ice-lg);
  padding: 36px 32px;
  box-shadow: var(--ice-bevel), var(--shadow-ice-md);
}

.article-faq-title {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--polar-navy);
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  gap: 10px;
}

/* Related Reading Section */
.related-reading-section {
  margin: 56px 0 40px;
  padding-top: 40px;
  border-top: 1px solid var(--ice-border-subtle);
}

.related-heading {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--polar-navy);
  margin-bottom: 24px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.related-card {
  padding: 22px 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.related-card h4 {
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.45;
  color: var(--polar-navy);
  margin-bottom: 10px;
}

.related-card:hover h4 {
  color: var(--cobalt-blue);
}

.related-meta {
  font-size: 0.8rem;
  color: var(--polar-muted);
}

/* ==========================================================================
   Responsive Adaptations (@media Queries)
   ========================================================================== */
@media (max-width: 1240px) {
  .nav-menu {
    gap: 6px;
  }
  .nav-link {
    font-size: 0.86rem;
    padding: 5px 8px;
  }
  .brand-logo {
    font-size: 1.25rem;
    gap: 8px;
  }
}

@media (max-width: 1100px) {
  .pricing-grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .pricing-card.featured {
    transform: none;
  }

  .pricing-card.featured:hover {
    transform: translateY(-4px);
  }
}

@media (max-width: 1040px) {
  .header-inner {
    height: 68px;
  }

  .nav-menu {
    position: fixed;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--frost-header);
    backdrop-filter: var(--frost-blur);
    border-bottom: 1px solid var(--ice-border);
    flex-direction: column;
    align-items: stretch;
    padding: 24px;
    gap: 12px;
    transform: translateY(-160%);
    opacity: 0;
    pointer-events: none;
    transition: all 0.35s var(--transition-liquid);
    box-shadow: var(--shadow-ice-lg);
    z-index: 999;
  }

  .nav-menu.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-link {
    font-size: 0.98rem;
    padding: 10px 16px;
    width: 100%;
    justify-content: flex-start;
  }

  .mobile-menu-btn {
    display: inline-flex;
  }
}

@media (max-width: 900px) {
  .core-features-grid,
  .showcase-grid,
  .testimonials-grid,
  .article-grid {
    grid-template-columns: 1fr;
  }

  .ping-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .pricing-grid-4 {
    grid-template-columns: 1fr;
  }

  .checkin-crystal-container {
    padding: 26px 20px;
  }

  .checkin-header-row {
    flex-direction: column;
    align-items: flex-start;
  }

  .footer-nav {
    flex-direction: column;
    gap: 18px;
  }

  .hero-cta-group {
    flex-direction: column;
    width: 100%;
  }

  .hero-cta-group .btn {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .container {
    padding-left: 18px;
    padding-right: 18px;
  }

  .brand-domain-pill {
    display: none;
  }

  .ping-grid {
    grid-template-columns: 1fr;
  }
}