/* =========================================================
   Keka 中国 - 软件推广网站
   设计风格：扁平现代专业 (Flat Modern Professional)
   配色基于 Keka Logo：温暖纸箱棕 + 金铜色强调
   ========================================================= */

/* ---------- CSS Variables ---------- */
:root {
  /* Brand palette - based on Keka logo (cardboard box brown) */
  --brand-primary: #6B4A2E;       /* 主品牌色 - 温暖木棕色 */
  --brand-primary-dark: #4A3220;  /* 深品牌色 - 浓缩咖啡棕 */
  --brand-primary-light: #8B6F47; /* 浅品牌色 */
  --brand-accent: #C8853D;        /* 强调色 - 金铜色 */
  --brand-accent-dark: #A66B26;   /* 深强调色 */
  --brand-accent-light: #E0A35A;  /* 浅强调色 */

  /* Backgrounds */
  --bg-main: #FBF8F3;             /* 主背景 - 暖奶油色 */
  --bg-alt: #F4EDE2;              /* 备用背景 - 略深奶油 */
  --bg-card: #FFFFFF;             /* 卡片背景 - 纯白 */
  --bg-dark: #2D1810;             /* 深色背景 - 深咖啡 */
  --bg-dark-alt: #3D2817;         /* 深色背景变体 */

  /* Text */
  --text-primary: #2D1810;        /* 主要文本 */
  --text-secondary: #6B5D4F;      /* 次要文本 */
  --text-muted: #9C8E7E;          /* 弱化文本 */
  --text-inverse: #FBF8F3;        /* 反色文本 */
  --text-on-accent: #FFFFFF;

  /* Borders & dividers */
  --border-light: #E8DDD0;        /* 浅边框 */
  --border-medium: #D4C4B0;       /* 中边框 */

  /* Functional */
  --success: #2D7A4A;
  --info: #2E5A8A;
  --warning: #B8741A;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(107, 74, 46, 0.06), 0 1px 2px rgba(107, 74, 46, 0.04);
  --shadow-md: 0 4px 12px rgba(107, 74, 46, 0.08), 0 2px 4px rgba(107, 74, 46, 0.04);
  --shadow-lg: 0 10px 30px rgba(107, 74, 46, 0.10), 0 4px 8px rgba(107, 74, 46, 0.06);
  --shadow-xl: 0 20px 50px rgba(107, 74, 46, 0.14), 0 8px 16px rgba(107, 74, 46, 0.08);
  --shadow-accent: 0 6px 20px rgba(200, 133, 61, 0.28);

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-pill: 999px;

  /* Spacing scale */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 40px;
  --space-2xl: 64px;
  --space-3xl: 96px;

  /* Container */
  --container-width: 1200px;
  --container-narrow: 880px;

  /* Transitions */
  --transition-fast: 0.18s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.45s cubic-bezier(0.4, 0, 0.2, 1);

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue",
               "Microsoft YaHei", "Source Han Sans CN", "Noto Sans SC", sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --font-serif: "PingFang SC", "Noto Serif SC", Georgia, serif;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
  -webkit-text-size-adjust: 100%;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-primary);
  background: var(--bg-main);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

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

a {
  color: var(--brand-accent-dark);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

ul, ol {
  list-style: none;
}

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

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
}

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

h1 {
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  font-weight: 800;
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  letter-spacing: -0.02em;
}

h3 {
  font-size: clamp(1.3rem, 2vw, 1.6rem);
}

h4 {
  font-size: 1.15rem;
}

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

p:last-child {
  margin-bottom: 0;
}

strong {
  color: var(--text-primary);
  font-weight: 600;
}

code {
  font-family: var(--font-mono);
  background: var(--bg-alt);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  font-size: 0.9em;
  color: var(--brand-primary-dark);
}

/* ---------- Layout ---------- */
.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

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

.section {
  padding: var(--space-3xl) 0;
}

.section-sm {
  padding: var(--space-2xl) 0;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto var(--space-2xl);
}

.section-eyebrow {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--brand-accent-dark);
  background: rgba(200, 133, 61, 0.10);
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  margin-bottom: var(--space-md);
}

.section-title {
  margin-bottom: var(--space-md);
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: 600;
  line-height: 1;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
  white-space: nowrap;
  border: 2px solid transparent;
  position: relative;
}

.btn-primary {
  background: var(--brand-accent);
  color: var(--text-on-accent);
  box-shadow: var(--shadow-accent);
}

.btn-primary:hover {
  background: var(--brand-accent-dark);
  color: var(--text-on-accent);
  transform: translateY(-2px);
  box-shadow: 0 10px 28px rgba(200, 133, 61, 0.38);
}

.btn-secondary {
  background: var(--brand-primary);
  color: var(--text-inverse);
}

.btn-secondary:hover {
  background: var(--brand-primary-dark);
  color: var(--text-inverse);
  transform: translateY(-2px);
}

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

.btn-outline:hover {
  border-color: var(--brand-primary);
  background: var(--bg-alt);
  color: var(--brand-primary);
}

.btn-ghost {
  background: transparent;
  color: var(--text-primary);
  padding: 10px 18px;
}

.btn-ghost:hover {
  background: var(--bg-alt);
  color: var(--brand-primary);
}

.btn-lg {
  padding: 18px 36px;
  font-size: 1.1rem;
}

.btn-sm {
  padding: 10px 20px;
  font-size: 0.9rem;
}

.btn-block {
  display: flex;
  width: 100%;
}

.btn-icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

/* ---------- Navbar ---------- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(251, 248, 243, 0.85);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid transparent;
  transition: all var(--transition-base);
}

.navbar.scrolled {
  background: rgba(251, 248, 243, 0.95);
  border-bottom-color: var(--border-light);
  box-shadow: var(--shadow-sm);
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.25rem;
  text-decoration: none;
}

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

.navbar-brand img {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
}

.navbar-brand span {
  letter-spacing: -0.01em;
}

.navbar-brand small {
  display: block;
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}

.navbar-menu {
  display: flex;
  align-items: center;
  gap: 8px;
}

.navbar-link {
  display: inline-flex;
  align-items: center;
  padding: 8px 16px;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.navbar-link:hover {
  color: var(--brand-primary);
  background: var(--bg-alt);
}

.navbar-link.active {
  color: var(--brand-primary);
  font-weight: 600;
}

.navbar-cta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-left: var(--space-md);
}

.navbar-toggle {
  display: none;
  width: 44px;
  height: 44px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  border-radius: var(--radius-sm);
  background: transparent;
  transition: background var(--transition-fast);
}

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

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

.navbar-toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.navbar-toggle.active span:nth-child(2) {
  opacity: 0;
}
.navbar-toggle.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: 160px 0 100px;
  overflow: hidden;
  background:
    radial-gradient(circle at 15% 20%, rgba(200, 133, 61, 0.08) 0%, transparent 40%),
    radial-gradient(circle at 85% 80%, rgba(107, 74, 46, 0.06) 0%, transparent 40%),
    var(--bg-main);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: var(--space-2xl);
  align-items: center;
}

.hero-content {
  max-width: 580px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: rgba(45, 122, 74, 0.10);
  color: var(--success);
  border-radius: var(--radius-pill);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: var(--space-lg);
}

.hero-badge .dot {
  width: 8px;
  height: 8px;
  background: var(--success);
  border-radius: 50%;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.3); }
}

.hero-title {
  margin-bottom: var(--space-lg);
}

.hero-title .accent {
  color: var(--brand-accent-dark);
  position: relative;
  display: inline-block;
}

.hero-title .accent::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 0;
  right: 0;
  height: 10px;
  background: rgba(200, 133, 61, 0.22);
  z-index: -1;
  border-radius: 4px;
}

.hero-subtitle {
  font-size: 1.15rem;
  line-height: 1.7;
  color: var(--text-secondary);
  margin-bottom: var(--space-xl);
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-lg) var(--space-2xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--border-light);
}

.hero-meta-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.hero-meta-num {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--brand-primary);
  line-height: 1;
  letter-spacing: -0.02em;
}

.hero-meta-label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

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

.hero-logo-card {
  position: relative;
  width: 100%;
  max-width: 420px;
  aspect-ratio: 1;
  background: linear-gradient(135deg, #FFFFFF 0%, #FBF8F3 100%);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border: 1px solid var(--border-light);
}

.hero-logo-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 30% 30%, rgba(200, 133, 61, 0.10) 0%, transparent 50%),
    radial-gradient(circle at 70% 70%, rgba(107, 74, 46, 0.08) 0%, transparent 50%);
  pointer-events: none;
}

.hero-logo-card img {
  width: 65%;
  height: auto;
  position: relative;
  z-index: 1;
  filter: drop-shadow(0 20px 40px rgba(107, 74, 46, 0.2));
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

.hero-floating-tag {
  position: absolute;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 10px 14px;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  z-index: 2;
}

.hero-floating-tag .icon {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 0.95rem;
}

.tag-1 {
  top: 8%;
  left: -5%;
  animation: float 5s ease-in-out infinite;
}

.tag-1 .icon { background: var(--brand-accent); }

.tag-2 {
  bottom: 15%;
  right: -8%;
  animation: float 5s ease-in-out infinite 0.5s;
}

.tag-2 .icon { background: var(--success); }

.tag-3 {
  bottom: -3%;
  left: 10%;
  animation: float 5s ease-in-out infinite 1s;
}

.tag-3 .icon { background: var(--brand-primary); }

/* ---------- Trust bar ---------- */
.trust-bar {
  padding: var(--space-xl) 0;
  background: var(--bg-card);
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.trust-bar-inner {
  display: flex;
  justify-content: space-around;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-lg);
}

.trust-item {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
}

.trust-item svg {
  width: 22px;
  height: 22px;
  color: var(--brand-accent);
}

/* ---------- Features grid ---------- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-lg);
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-lg);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--brand-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}

.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--border-medium);
}

.feature-card:hover::before {
  transform: scaleX(1);
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--brand-accent) 0%, var(--brand-accent-dark) 100%);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-md);
  box-shadow: 0 6px 18px rgba(200, 133, 61, 0.25);
}

.feature-icon svg {
  width: 28px;
  height: 28px;
}

.feature-card h3 {
  margin-bottom: var(--space-sm);
  color: var(--text-primary);
}

.feature-card p {
  font-size: 0.95rem;
  line-height: 1.7;
  margin: 0;
}

/* ---------- Usage scenarios ---------- */
.scenarios {
  background: var(--bg-alt);
}

.scenarios-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-lg);
}

.scenario-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-light);
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
}

.scenario-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.scenario-illustration {
  height: 160px;
  background: linear-gradient(135deg, var(--brand-primary-light) 0%, var(--brand-accent-light) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  position: relative;
  overflow: hidden;
}

.scenario-illustration::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 30%, rgba(255,255,255,0.2) 0%, transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(0,0,0,0.1) 0%, transparent 40%);
}

.scenario-illustration svg {
  width: 64px;
  height: 64px;
  position: relative;
  z-index: 1;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.15));
}

.scenario-body {
  padding: var(--space-lg);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.scenario-body h3 {
  margin-bottom: var(--space-sm);
  font-size: 1.15rem;
}

.scenario-body p {
  font-size: 0.95rem;
  margin-bottom: var(--space-md);
  flex: 1;
}

.scenario-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--brand-accent-dark);
  background: rgba(200, 133, 61, 0.10);
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  align-self: flex-start;
}

/* ---------- Format support ---------- */
.formats {
  background: var(--bg-card);
}

.formats-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-2xl);
  align-items: start;
}

.formats-panel {
  background: var(--bg-main);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
}

.formats-panel h3 {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: var(--space-md);
  font-size: 1.25rem;
}

.formats-panel h3 .badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: var(--radius-pill);
  color: #fff;
}

.formats-panel.compress h3 .badge { background: var(--brand-accent); }
.formats-panel.decompress h3 .badge { background: var(--brand-primary); }

.formats-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.format-chip {
  display: inline-flex;
  align-items: center;
  padding: 6px 12px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.format-chip:hover {
  border-color: var(--brand-accent);
  background: rgba(200, 133, 61, 0.06);
  color: var(--brand-accent-dark);
  transform: translateY(-1px);
}

/* ---------- User reviews ---------- */
.reviews {
  background: var(--bg-alt);
}

.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-lg);
}

.review-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-lg);
  border: 1px solid var(--border-light);
  position: relative;
  transition: all var(--transition-base);
}

.review-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.review-quote-mark {
  position: absolute;
  top: 16px;
  right: 20px;
  font-family: Georgia, serif;
  font-size: 4rem;
  line-height: 1;
  color: var(--brand-accent);
  opacity: 0.2;
}

.review-rating {
  display: flex;
  gap: 2px;
  margin-bottom: var(--space-md);
  color: var(--brand-accent);
}

.review-rating svg {
  width: 18px;
  height: 18px;
}

.review-text {
  font-size: 0.98rem;
  line-height: 1.75;
  color: var(--text-primary);
  margin-bottom: var(--space-lg);
  position: relative;
  z-index: 1;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-top: var(--space-md);
  border-top: 1px solid var(--border-light);
}

.review-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand-primary-light), var(--brand-accent));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
}

.review-author-info {
  flex: 1;
}

.review-author-name {
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.95rem;
}

.review-author-meta {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* ---------- Stats band ---------- */
.stats-band {
  background: var(--bg-dark);
  color: var(--text-inverse);
  padding: var(--space-2xl) 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--space-xl);
  text-align: center;
}

.stat-item {
  padding: var(--space-md);
}

.stat-num {
  font-size: clamp(2.2rem, 4vw, 3rem);
  font-weight: 800;
  color: var(--brand-accent-light);
  line-height: 1;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-sm);
}

.stat-label {
  font-size: 0.95rem;
  color: rgba(251, 248, 243, 0.7);
}

/* ---------- CTA section ---------- */
.cta-section {
  background: linear-gradient(135deg, var(--brand-primary) 0%, var(--brand-primary-dark) 100%);
  color: var(--text-inverse);
  padding: var(--space-2xl) 0;
  position: relative;
  overflow: hidden;
}

.cta-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 30%, rgba(200, 133, 61, 0.15) 0%, transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(200, 133, 61, 0.10) 0%, transparent 40%);
}

.cta-inner {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 720px;
  margin: 0 auto;
}

.cta-section h2 {
  color: var(--text-inverse);
  margin-bottom: var(--space-md);
}

.cta-section p {
  color: rgba(251, 248, 243, 0.85);
  font-size: 1.1rem;
  margin-bottom: var(--space-xl);
}

.cta-section .btn-primary {
  background: var(--brand-accent);
}

.cta-section .btn-primary:hover {
  background: var(--brand-accent-light);
}

.cta-section .btn-outline {
  border-color: rgba(251, 248, 243, 0.4);
  color: var(--text-inverse);
}

.cta-section .btn-outline:hover {
  border-color: var(--text-inverse);
  background: rgba(251, 248, 243, 0.10);
  color: var(--text-inverse);
}

/* ---------- Footer ---------- */
.footer {
  background: var(--bg-dark);
  color: rgba(251, 248, 243, 0.7);
  padding: var(--space-2xl) 0 var(--space-xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

.footer-brand {
  max-width: 320px;
}

.footer-brand .navbar-brand {
  color: var(--text-inverse);
  margin-bottom: var(--space-md);
}

.footer-brand .navbar-brand:hover {
  color: var(--brand-accent-light);
}

.footer-brand p {
  color: rgba(251, 248, 243, 0.6);
  font-size: 0.9rem;
  line-height: 1.7;
}

.footer-col h4 {
  color: var(--text-inverse);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
  letter-spacing: 0.02em;
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col a {
  color: rgba(251, 248, 243, 0.6);
  font-size: 0.9rem;
  transition: color var(--transition-fast);
}

.footer-col a:hover {
  color: var(--brand-accent-light);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-md);
  padding-top: var(--space-lg);
  border-top: 1px solid rgba(251, 248, 243, 0.10);
  font-size: 0.85rem;
  color: rgba(251, 248, 243, 0.5);
}

.footer-social {
  display: flex;
  gap: 12px;
}

.footer-social a {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: rgba(251, 248, 243, 0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(251, 248, 243, 0.7);
  transition: all var(--transition-fast);
}

.footer-social a:hover {
  background: var(--brand-accent);
  color: #fff;
  transform: translateY(-2px);
}

.footer-social svg {
  width: 18px;
  height: 18px;
}

/* ---------- Modal (Download popup) ---------- */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(45, 24, 16, 0.55);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-lg);
  z-index: 2000;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base), visibility var(--transition-base);
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: var(--bg-card);
  border-radius: var(--radius-xl);
  max-width: 720px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-xl);
  transform: scale(0.92) translateY(20px);
  transition: transform var(--transition-base);
  position: relative;
}

.modal-overlay.active .modal {
  transform: scale(1) translateY(0);
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--bg-alt);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  line-height: 1;
  transition: all var(--transition-fast);
  z-index: 2;
}

.modal-close:hover {
  background: var(--brand-primary);
  color: #fff;
  transform: rotate(90deg);
}

.modal-header {
  padding: var(--space-xl) var(--space-xl) var(--space-lg);
  text-align: center;
  border-bottom: 1px solid var(--border-light);
}

.modal-header img {
  width: 72px;
  height: 72px;
  margin: 0 auto var(--space-md);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
}

.modal-header h3 {
  font-size: 1.5rem;
  margin-bottom: var(--space-sm);
}

.modal-header p {
  color: var(--text-secondary);
  margin: 0;
  font-size: 0.95rem;
}

.modal-body {
  padding: var(--space-xl);
}

.modal-qr-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.modal-qr-item {
  text-align: center;
  padding: var(--space-lg);
  background: var(--bg-main);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
  transition: all var(--transition-base);
}

.modal-qr-item:hover {
  border-color: var(--brand-accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.modal-qr-item img {
  width: 180px;
  height: 180px;
  margin: 0 auto var(--space-md);
  border-radius: var(--radius-sm);
  background: #fff;
  padding: 8px;
}

.modal-qr-item h4 {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-bottom: 6px;
  font-size: 1.05rem;
}

.modal-qr-item h4 .platform-icon {
  width: 20px;
  height: 20px;
}

.modal-qr-item p {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 0;
}

.modal-cta {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

.modal-info {
  margin-top: var(--space-lg);
  padding: var(--space-md);
  background: var(--bg-alt);
  border-radius: var(--radius-md);
  font-size: 0.88rem;
  color: var(--text-secondary);
  text-align: center;
}

.modal-info strong {
  color: var(--brand-primary);
}

/* ---------- Page hero (sub pages) ---------- */
.page-hero {
  padding: 140px 0 80px;
  background:
    radial-gradient(circle at 20% 30%, rgba(200, 133, 61, 0.08) 0%, transparent 40%),
    var(--bg-main);
  text-align: center;
  border-bottom: 1px solid var(--border-light);
}

.page-hero h1 {
  margin-bottom: var(--space-md);
}

.page-hero p {
  max-width: 640px;
  margin: 0 auto;
  font-size: 1.1rem;
}

.breadcrumb {
  display: flex;
  justify-content: center;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: var(--space-md);
}

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

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

.breadcrumb .sep {
  color: var(--border-medium);
}

/* ---------- Download page ---------- */
.download-platforms {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--space-lg);
  margin-bottom: var(--space-2xl);
}

.platform-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.platform-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--brand-accent);
}

.platform-card.featured {
  border-color: var(--brand-accent);
  background: linear-gradient(135deg, #FFFFFF 0%, #FFFBF3 100%);
}

.platform-card.featured::before {
  content: '推荐';
  position: absolute;
  top: 16px;
  right: 16px;
  background: var(--brand-accent);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
}

.platform-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: var(--space-md);
}

.platform-icon-lg {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  flex-shrink: 0;
}

.platform-icon-lg.mac { background: linear-gradient(135deg, #6B4A2E, #4A3220); }
.platform-icon-lg.ios { background: linear-gradient(135deg, #C8853D, #A66B26); }

.platform-icon-lg svg {
  width: 32px;
  height: 32px;
}

.platform-header h3 {
  margin: 0;
  font-size: 1.3rem;
}

.platform-header .version {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.platform-spec {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: var(--space-lg);
  padding: var(--space-md) 0;
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.platform-spec-item {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
}

.platform-spec-item .label {
  color: var(--text-muted);
}

.platform-spec-item .value {
  color: var(--text-primary);
  font-weight: 500;
}

.platform-qr {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md);
  background: var(--bg-main);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-md);
}

.platform-qr img {
  width: 100px;
  height: 100px;
  border-radius: var(--radius-sm);
  background: #fff;
  padding: 4px;
  flex-shrink: 0;
}

.platform-qr-info {
  flex: 1;
}

.platform-qr-info h4 {
  font-size: 0.95rem;
  margin-bottom: 4px;
}

.platform-qr-info p {
  font-size: 0.82rem;
  margin: 0;
  color: var(--text-muted);
}

/* Version history table */
.version-table {
  width: 100%;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-light);
  border-collapse: collapse;
}

.version-table thead {
  background: var(--bg-alt);
}

.version-table th {
  text-align: left;
  padding: var(--space-md) var(--space-lg);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-light);
}

.version-table td {
  padding: var(--space-md) var(--space-lg);
  font-size: 0.92rem;
  border-bottom: 1px solid var(--border-light);
  color: var(--text-secondary);
}

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

.version-table tr:hover td {
  background: var(--bg-main);
}

.version-table .v-num {
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--brand-primary);
}

.version-table .v-current {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  background: var(--success);
  color: #fff;
  padding: 2px 8px;
  border-radius: var(--radius-pill);
  margin-left: 8px;
}

/* ---------- FAQ ---------- */
.faq-list {
  max-width: 760px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-md);
  overflow: hidden;
  transition: all var(--transition-fast);
}

.faq-item.active {
  border-color: var(--brand-accent);
  box-shadow: var(--shadow-md);
}

.faq-question {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-md) var(--space-lg);
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  color: var(--text-primary);
  background: transparent;
  transition: color var(--transition-fast);
}

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

.faq-question .chevron {
  width: 20px;
  height: 20px;
  color: var(--text-muted);
  transition: transform var(--transition-base);
  flex-shrink: 0;
}

.faq-item.active .faq-question .chevron {
  transform: rotate(180deg);
  color: var(--brand-accent);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-base);
}

.faq-item.active .faq-answer {
  max-height: 500px;
}

.faq-answer-inner {
  padding: 0 var(--space-lg) var(--space-md);
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.75;
}

/* ---------- About page ---------- */
.about-mission {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  text-align: center;
  max-width: 880px;
  margin: 0 auto var(--space-2xl);
  border: 1px solid var(--border-light);
}

.about-mission .quote-mark {
  font-family: Georgia, serif;
  font-size: 5rem;
  line-height: 0.5;
  color: var(--brand-accent);
  opacity: 0.3;
  margin-bottom: var(--space-md);
}

.about-mission p {
  font-size: 1.2rem;
  line-height: 1.8;
  color: var(--text-primary);
  font-weight: 500;
}

.timeline {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  padding-left: 40px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 12px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--brand-accent), var(--brand-primary));
}

.timeline-item {
  position: relative;
  padding-bottom: var(--space-xl);
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -34px;
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 3px solid var(--brand-accent);
}

.timeline-item .year {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--brand-accent-dark);
  margin-bottom: 4px;
}

.timeline-item h4 {
  margin-bottom: 6px;
}

.timeline-item p {
  margin: 0;
  font-size: 0.95rem;
}

.values-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-lg);
}

.value-card {
  text-align: center;
  padding: var(--space-xl) var(--space-lg);
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
}

.value-card .icon-circle {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: rgba(200, 133, 61, 0.10);
  color: var(--brand-accent-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--space-md);
}

.value-card .icon-circle svg {
  width: 30px;
  height: 30px;
}

.value-card h4 {
  margin-bottom: var(--space-sm);
}

.value-card p {
  font-size: 0.92rem;
  margin: 0;
}

/* ---------- Animations ---------- */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease-out, transform 0.7s ease-out;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ---------- Back to top ---------- */
.back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--brand-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-base);
  z-index: 900;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--brand-primary-dark);
  transform: translateY(-3px);
}

.back-to-top svg {
  width: 22px;
  height: 22px;
}

/* ---------- Responsive ---------- */
@media (max-width: 968px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }

  .hero-visual {
    order: -1;
  }

  .hero-logo-card {
    max-width: 320px;
  }

  .formats-layout {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
  }

  .footer-brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 768px) {
  :root {
    --space-3xl: 64px;
    --space-2xl: 48px;
  }

  .navbar-menu {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--bg-main);
    flex-direction: column;
    align-items: stretch;
    padding: var(--space-md) var(--space-lg) var(--space-xl);
    gap: var(--space-xs);
    border-bottom: 1px solid var(--border-light);
    box-shadow: var(--shadow-lg);
    transform: translateY(-120%);
    transition: transform var(--transition-base);
    max-height: calc(100vh - 72px);
    overflow-y: auto;
  }

  .navbar-menu.active {
    transform: translateY(0);
  }

  .navbar-link {
    padding: 12px 16px;
    font-size: 1rem;
  }

  .navbar-cta {
    margin-left: 0;
    margin-top: var(--space-sm);
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
  }

  .navbar-cta .btn {
    width: 100%;
  }

  .navbar-toggle {
    display: flex;
  }

  .hero {
    padding: 120px 0 60px;
  }

  .hero-cta {
    flex-direction: column;
  }

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

  .modal-qr-grid {
    grid-template-columns: 1fr;
  }

  .modal-qr-item img {
    width: 160px;
    height: 160px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--space-md);
  }

  .hero-meta {
    gap: var(--space-md);
  }

  .modal {
    border-radius: var(--radius-lg);
  }

  .modal-header, .modal-body {
    padding: var(--space-lg);
  }
}

/* ---------- Print ---------- */
@media print {
  .navbar, .back-to-top, .modal-overlay, .footer-social {
    display: none !important;
  }
}

/* ---------- Accessibility ---------- */
@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;
  }
}

:focus-visible {
  outline: 2px solid var(--brand-accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

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