/* ============================================
   快连加速器 - 公共样式
   简约浅色调设计系统
   ============================================ */

/* ---------- CSS 变量 ---------- */
:root {
  --primary: #4F6EF7;
  --primary-light: #6B85FF;
  --primary-dark: #3A56D4;
  --primary-bg: #EEF1FE;
  --accent: #22C997;
  --accent-light: #34D4A8;
  --accent-bg: #E6F9F3;

  --text-primary: #1A1D26;
  --text-secondary: #5A6178;
  --text-muted: #6B7385;
  --text-white: #FFFFFF;

  --bg-white: #FFFFFF;
  --bg-page: #F6F7FB;
  --bg-card: rgba(255,255,255,0.62);
  --bg-footer: #1A1D26;

  --border: #E8EBF2;
  --border-light: #F0F2F7;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.06);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.08);
  --shadow-primary: 0 4px 20px rgba(79,110,247,0.25);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 999px;

  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --container: 1140px;
  --transition: 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  scroll-padding-top: 84px;
}

body {
  font-family: var(--font-family);
  color: var(--text-primary);
  background: var(--bg-page);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

ul, ol {
  list-style: none;
}

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

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

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

/* ---------- Navigation ---------- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-light);
  transition: box-shadow var(--transition);
}

.nav.scrolled {
  box-shadow: var(--shadow-sm);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
}

.nav-logo .logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 18px;
  font-weight: 800;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-links a {
  font-size: 15px;
  color: var(--text-secondary);
  font-weight: 500;
  transition: color var(--transition);
  position: relative;
}

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

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--primary);
  border-radius: 1px;
}

.nav-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 20px;
  background: var(--primary);
  color: white;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: all var(--transition);
}

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

.nav-btn svg {
  width: 16px;
  height: 16px;
}

/* Mobile Menu */
.nav-mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}

.nav-mobile-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 1px;
  transition: all var(--transition);
}

.nav-mobile-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-mobile-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-mobile-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: all var(--transition);
  white-space: nowrap;
}

.btn svg {
  width: 18px;
  height: 18px;
}

/* Icon baseline: uniform rounded line ends for all line icons */
svg[stroke] {
  stroke-linecap: round;
  stroke-linejoin: round;
}

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

.btn-primary:hover {
  background: var(--primary-dark);
  box-shadow: var(--shadow-primary);
  transform: translateY(-2px);
}

.btn-outline {
  border: 1.5px solid var(--border);
  color: var(--text-primary);
  background: var(--bg-white);
}

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

.btn-large {
  padding: 16px 36px;
  font-size: 16px;
}

.btn-small {
  padding: 8px 18px;
  font-size: 13px;
}

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

.btn-accent:hover {
  background: #1DB88A;
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(34,201,151,0.3);
}

/* ---------- Section ---------- */
.section {
  padding: 80px 0;
}

.section-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 48px;
}

.section-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: var(--primary-bg);
  color: var(--primary);
  font-size: 13px;
  font-weight: 600;
  border-radius: var(--radius-full);
  margin-bottom: 16px;
}

.section-badge svg {
  width: 14px;
  height: 14px;
}

.section-title {
  font-size: 32px;
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
  margin-bottom: 14px;
}

.section-desc {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ---------- Cards ---------- */
.card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  -webkit-backdrop-filter: blur(14px) saturate(160%);
  backdrop-filter: blur(14px) saturate(160%);
  transition: all var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--primary);
  transform: translateY(-2px);
}

/* ---------- Footer ---------- */
.footer {
  background: var(--bg-footer);
  color: rgba(255,255,255,0.7);
  padding: 48px 0 24px;
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 32px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-brand .footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
}

.footer-brand .footer-logo .logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 16px;
  font-weight: 800;
}

.footer-brand p {
  font-size: 14px;
  line-height: 1.7;
  max-width: 280px;
}

.footer-col h4 {
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 16px;
}

.footer-col a {
  display: block;
  font-size: 14px;
  padding: 4px 0;
  transition: color var(--transition);
}

.footer-col a:hover {
  color: #fff;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 24px;
  font-size: 13px;
  color: rgba(255,255,255,0.4);
}

/* ---------- Animations ---------- */
.js .fade-up {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    justify-content: center;
    gap: 24px;
    z-index: 999;
  }

  .nav-links.active {
    display: flex;
  }

  .nav-links a {
    font-size: 20px;
  }

  .nav-mobile-toggle {
    display: flex;
  }

  .section {
    padding: 56px 0;
  }

  .section-title {
    font-size: 26px;
  }

  .section-desc {
    font-size: 15px;
  }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: 28px;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 8px;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .footer-inner {
    grid-template-columns: 1fr;
  }
  .container {
    padding: 0 20px;
  }
}

/* ---------- A11y: focus visible & skip-link ---------- */
:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}
@supports not selector(:focus-visible) {
  *:focus {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
  }
}

.skip-link {
  position: absolute;
  left: 16px;
  top: -48px;
  z-index: 2000;
  padding: 10px 18px;
  background: var(--primary);
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: top var(--transition);
}
.skip-link:focus {
  top: 16px;
}

/* ---------- Logo image (iconkuailian.jpg) ---------- */
.logo-img {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  object-fit: cover;
  flex-shrink: 0;
}
.footer-logo .logo-img {
  width: 32px;
  height: 32px;
  border-radius: 8px;
}

/* ---------- Download card icon variants ---------- */
.download-card-icon.icon-win { background:#E8F0FE; color:#0078D4; }
.download-card-icon.icon-mac { background:#F0E8FE; color:#7B61FF; }
.download-card-icon.icon-and { background:#E6F9F3; color:#22C997; }
.download-card-icon.icon-ios { background:#FFF0E8; color:#FF6B35; }

/* ---------- Utility ---------- */
.mt-32 { margin-top: 32px; }

/* ============================================================
   深色模式 · 玻璃拟态 · 主题切换  (kl1 视觉升级)
   ============================================================ */

/* 全局极光背景层：玻璃卡片透出层次 */
body {
  background-color: var(--bg-page);
  background-image:
    radial-gradient(58vw 50vw at 8% -10%, rgba(79,110,247,0.12), transparent 60%),
    radial-gradient(46vw 46vw at 96% 2%, rgba(34,201,151,0.10), transparent 58%),
    radial-gradient(44vw 42vw at 50% 112%, rgba(123,97,255,0.09), transparent 58%);
  background-attachment: fixed;
}

/* 玻璃拟态基类 */
.glass {
  background: var(--bg-card);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  backdrop-filter: blur(16px) saturate(160%);
  border: 1px solid var(--border);
}

/* 主题切换按钮 */
.theme-toggle {
  width: 38px;
  height: 38px;
  flex-shrink: 0;
  margin-right: 12px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  transition: all var(--transition);
}
.theme-toggle:hover { color: var(--primary); border-color: var(--primary); transform: translateY(-1px); }
.theme-toggle svg { width: 18px; height: 18px; }
.theme-toggle .icon-sun { display: none; }
.theme-toggle .icon-moon { display: block; }

/* 导航深色适配 */
[data-theme="dark"] .nav {
  background: rgba(13,15,21,0.82);
  border-bottom-color: rgba(255,255,255,0.08);
}
[data-theme="dark"] .nav-links {
  background: rgba(13,15,21,0.98);
}
[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

/* ---------- 深色令牌 ---------- */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --primary: #6B85FF;
    --primary-light: #8FA0FF;
    --primary-dark: #4F6EF7;
    --primary-bg: rgba(79,110,247,0.16);
    --accent: #34D4A8;
    --accent-light: #4FE0BC;
    --accent-bg: rgba(34,201,151,0.14);
    --text-primary: #ECEEF5;
    --text-secondary: #A9B0C4;
    --text-muted: #828AA0;
    --bg-white: #161922;
    --bg-page: #0D0F15;
    --bg-card: rgba(255,255,255,0.045);
    --bg-footer: #070809;
    --border: rgba(255,255,255,0.10);
    --border-light: rgba(255,255,255,0.07);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.40);
    --shadow-md: 0 4px 20px rgba(0,0,0,0.45);
    --shadow-lg: 0 8px 40px rgba(0,0,0,0.50);
    --shadow-primary: 0 4px 24px rgba(79,110,247,0.45);
  }
  :root:not([data-theme="light"]) .nav {
    background: rgba(13,15,21,0.82);
    border-bottom-color: rgba(255,255,255,0.08);
  }
  :root:not([data-theme="light"]) .nav-links {
    background: rgba(13,15,21,0.98);
  }
  :root:not([data-theme="light"]) .theme-toggle .icon-sun { display: block; }
  :root:not([data-theme="light"]) .theme-toggle .icon-moon { display: none; }
}
[data-theme="dark"] {
  --primary: #6B85FF;
  --primary-light: #8FA0FF;
  --primary-dark: #4F6EF7;
  --primary-bg: rgba(79,110,247,0.16);
  --accent: #34D4A8;
  --accent-light: #4FE0BC;
  --accent-bg: rgba(34,201,151,0.14);
  --text-primary: #ECEEF5;
  --text-secondary: #A9B0C4;
  --text-muted: #828AA0;
  --bg-white: #161922;
  --bg-page: #0D0F15;
  --bg-card: rgba(255,255,255,0.045);
  --bg-footer: #070809;
  --border: rgba(255,255,255,0.10);
  --border-light: rgba(255,255,255,0.07);
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.40);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.45);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.50);
  --shadow-primary: 0 4px 24px rgba(79,110,247,0.45);
}

/* fade-up 无 JS / 减少动效时直接可见，避免整页空白 */
@media (prefers-reduced-motion: reduce) {
  .fade-up { opacity: 1 !important; transform: none !important; }
}

/* 404 页面 */
.notfound { padding: 120px 0; text-align: center; }
.notfound-inner { max-width: 560px; margin: 0 auto; }
.notfound-code {
  font-size: 96px; font-weight: 800; line-height: 1;
  background: linear-gradient(135deg, #4f6ef7, #6a8bff);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.notfound-title { margin: 16px 0 8px; font-size: 28px; }
.notfound-desc { color: #6b7280; margin-bottom: 32px; }
.notfound-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }