@charset "UTF-8";

/* ================================================
   AO3 免费存档平台 · 入口指南 - 主样式表
   主题：深空暗底 + 高饱和红渐变 + 光晕（大众爆款风格）
   响应式断点：992px / 768px / 480px
   ================================================ */

/* ---------- 设计令牌 ---------- */
:root {
  /* 背景：近黑暖调，衬得红色更亮 */
  --c-bg: #0B0709;
  --c-bg-alt: #120B0E;
  --c-surface: rgba(255, 255, 255, .045);
  --c-surface-hover: rgba(255, 59, 71, .09);
  --c-border: rgba(255, 255, 255, .09);
  --c-border-strong: rgba(255, 255, 255, .17);

  /* 主色：高饱和正红 */
  --c-primary: #FF3B47;
  --c-primary-2: #E11D2E;
  --c-primary-dark: #B00E22;

  /* 高亮：玫瑰粉（深色底上更抓眼） */
  --c-hl: #FFB3BE;
  --c-hl-2: #FF6B7A;

  /* 文字 */
  --c-text: #FFFFFF;
  --c-text-2: rgba(255, 255, 255, .68);
  --c-text-3: rgba(255, 255, 255, .45);
  --c-text-inv: #FFFFFF;
  --c-text-inv-2: rgba(255, 255, 255, .68);

  /* 光晕 */
  --glow-sm: 0 8px 22px rgba(255, 45, 60, .28);
  --glow-md: 0 12px 32px rgba(255, 45, 60, .4);
  --glow-lg: 0 20px 50px rgba(255, 45, 60, .5);

  /* 圆角 */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;

  /* 动效 */
  --t-fast: .2s ease;
  --t-normal: .35s cubic-bezier(.22, .61, .36, 1);
  --t-slow: .6s ease;

  /* 布局 */
  --max-width: 1180px;
  --nav-height: 74px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 16px);
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", "Segoe UI", sans-serif;
  color: var(--c-text);
  background-color: var(--c-bg);
  line-height: 1.75;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  -webkit-tap-highlight-color: transparent;
  text-decoration: none;
  color: inherit;
}

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

ul {
  list-style: none;
}

h1, h2, h3 {
  font-family: Georgia, "Songti SC", "Noto Serif SC", "Source Han Serif SC", "SimSun", serif;
  font-weight: 700;
  line-height: 1.28;
  color: var(--c-text);
}

.icon {
  width: 20px;
  height: 20px;
  flex: none;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

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

/* ---------- 滚动淡入动画 ---------- */
.fade-in-up {
  opacity: 0;
  transform: translateY(36px);
  transition: opacity .8s ease, transform .8s ease;
}

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

.fade-in-up[data-delay="1"] { transition-delay: .12s; }
.fade-in-up[data-delay="2"] { transition-delay: .24s; }
.fade-in-up[data-delay="3"] { transition-delay: .36s; }
.fade-in-up[data-delay="4"] { transition-delay: .48s; }
.fade-in-up[data-delay="5"] { transition-delay: .6s; }
.fade-in-up[data-delay="6"] { transition-delay: .72s; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .fade-in-up { opacity: 1; transform: none; transition: none; }
}

/* ---------- 通用按钮 ---------- */
.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 15px 30px;
  border: none;
  border-radius: var(--radius-full);
  font-family: inherit;
  font-size: 16px;
  font-weight: 600;
  line-height: 1;
  cursor: pointer;
  white-space: nowrap;
  transition: transform var(--t-fast), box-shadow var(--t-fast), background var(--t-fast), color var(--t-fast), border-color var(--t-fast);
}

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

.btn-primary {
  background: linear-gradient(135deg, #FF4A54 0%, #E11D2E 52%, #BE0F23 100%);
  color: #FFFFFF;
  box-shadow: var(--glow-sm), inset 0 1px 0 rgba(255, 255, 255, .28);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--glow-lg), inset 0 1px 0 rgba(255, 255, 255, .28);
}

.btn-outline {
  background: rgba(255, 255, 255, .06);
  border: 1.5px solid rgba(255, 255, 255, .24);
  color: #FFFFFF;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, .13);
  border-color: rgba(255, 255, 255, .5);
  transform: translateY(-2px);
}

.btn-outline-dark {
  background: rgba(255, 255, 255, .05);
  border: 1.5px solid rgba(255, 255, 255, .2);
  color: #FFFFFF;
}

.btn-outline-dark:hover {
  border-color: rgba(255, 59, 71, .7);
  color: var(--c-hl);
  background: rgba(255, 59, 71, .12);
  transform: translateY(-2px);
}

/* ================================================
   导航栏
   ================================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  background: rgba(11, 7, 9, .5);
  transition: background var(--t-normal), box-shadow var(--t-normal);
}

/* 磨砂玻璃放在伪元素上，不要直接加在 .navbar 上：
   带 backdrop-filter / filter / transform 的元素会成为 fixed 子元素的包含块，
   移动端抽屉菜单会因此以导航栏为参照，高度被压缩成一条，点开后看不到内容 */
.navbar::before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: -1;
  pointer-events: none;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.navbar.scrolled {
  background: rgba(11, 7, 9, .92);
  box-shadow: 0 10px 34px rgba(0, 0, 0, .55), 0 1px 0 rgba(255, 255, 255, .07);
}

.navbar-logo {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: #FFFFFF;
}

.navbar-logo img {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: #FFFFFF;
  object-fit: contain;
  padding: 3px;
  box-shadow: 0 0 0 1px rgba(255, 255, 255, .14), 0 6px 18px rgba(255, 45, 60, .3);
}

.logo-text {
  display: flex;
  flex-direction: column;
  font-family: Georgia, "Songti SC", serif;
  font-size: 21px;
  font-weight: 700;
  letter-spacing: .06em;
  line-height: 1.15;
}

.logo-text small {
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 11px;
  font-weight: 400;
  letter-spacing: .16em;
  color: rgba(255, 255, 255, .55);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 30px;
}

.nav-menu a {
  position: relative;
  font-size: 15px;
  color: rgba(255, 255, 255, .74);
  transition: color var(--t-fast);
}

.nav-menu a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -7px;
  width: 0;
  height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, #FF4A54, #FF6B7A);
  box-shadow: 0 0 10px rgba(255, 59, 71, .8);
  transition: width var(--t-normal);
}

.nav-menu a:hover,
.nav-menu a.active { color: #FFFFFF; }

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

.btn-nav {
  padding: 11px 24px;
  font-size: 14px;
  background: linear-gradient(135deg, #FF4A54 0%, #E11D2E 52%, #BE0F23 100%);
  color: #FFFFFF;
  box-shadow: var(--glow-sm);
}

.btn-nav:hover { transform: translateY(-2px); }

.nav-cta-item { display: none; }

/* 汉堡按钮 */
.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: 1px solid rgba(255, 255, 255, .14);
  border-radius: 12px;
  background: rgba(255, 255, 255, .07);
  cursor: pointer;
  position: relative;
  /* 必须高于抽屉(999)，否则展开后按钮被抽屉盖住，既看不到 X 也点不动 */
  z-index: 1001;
  transition: background var(--t-fast);
}

.nav-toggle:hover { background: rgba(255, 255, 255, .15); }

.nav-toggle i,
.nav-toggle i::before,
.nav-toggle i::after {
  position: absolute;
  left: 50%;
  width: 20px;
  height: 2px;
  border-radius: 2px;
  background: #FFFFFF;
  transform: translateX(-50%);
  transition: transform var(--t-fast), opacity var(--t-fast), top var(--t-fast);
}

.nav-toggle i { top: 50%; margin-top: -1px; }
.nav-toggle i::before { content: ""; top: -7px; }
.nav-toggle i::after { content: ""; top: 7px; }

.nav-toggle.active i { background: transparent; }
.nav-toggle.active i::before { top: 0; transform: translateX(-50%) rotate(45deg); }
.nav-toggle.active i::after { top: 0; transform: translateX(-50%) rotate(-45deg); }

.nav-overlay {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 998;
  background: rgba(4, 2, 3, .7);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--t-normal), visibility var(--t-normal);
}

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

/* ================================================
   Hero 主视觉
   ================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  overflow: hidden;
  padding: calc(var(--nav-height) + 72px) 24px 120px;
  color: #FFFFFF;
  background:
    radial-gradient(960px 540px at 50% -12%, rgba(255, 59, 71, .5) 0%, rgba(255, 59, 71, 0) 62%),
    radial-gradient(720px 440px at 88% 104%, rgba(255, 45, 85, .26) 0%, rgba(255, 45, 85, 0) 62%),
    linear-gradient(165deg, #1C0C11 0%, #100809 55%, #0B0709 100%);
}

.hero-deco {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  pointer-events: none;
  overflow: hidden;
}

.hero-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(70px);
  opacity: .55;
}

.hero-orb-1 {
  width: 440px;
  height: 440px;
  top: -130px;
  left: -120px;
  background: radial-gradient(circle, rgba(255, 59, 71, .55), transparent 70%);
}

.hero-orb-2 {
  width: 500px;
  height: 500px;
  right: -150px;
  bottom: -170px;
  background: radial-gradient(circle, rgba(255, 45, 85, .38), transparent 70%);
}

.hero-grid {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, .05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, .05) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 70% 60% at 50% 45%, #000 20%, transparent 78%);
  -webkit-mask-image: radial-gradient(ellipse 70% 60% at 50% 45%, #000 20%, transparent 78%);
}

.hero-content {
  position: relative;
  z-index: 2;
  width: 100%;
  max-width: 900px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 9px 20px;
  margin-bottom: 30px;
  border: 1px solid rgba(255, 59, 71, .38);
  border-radius: var(--radius-full);
  background: rgba(255, 59, 71, .12);
  color: #FFC6CD;
  font-size: 14px;
  letter-spacing: .04em;
  box-shadow: 0 0 26px rgba(255, 59, 71, .22) inset;
}

.hero-badge i {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--c-hl-2);
  box-shadow: 0 0 0 4px rgba(255, 107, 122, .26);
  animation: pulse 2.4s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 4px rgba(255, 107, 122, .26); }
  50% { box-shadow: 0 0 0 10px rgba(255, 107, 122, .05); }
}

.hero-title {
  font-size: 2.4rem;
  font-size: clamp(2.1rem, 5.6vw, 4rem);
  letter-spacing: .01em;
  margin-bottom: 26px;
  color: #FFFFFF;
  text-shadow: 0 0 70px rgba(255, 59, 71, .45), 0 12px 40px rgba(0, 0, 0, .5);
}

.hero-title .highlight {
  background: linear-gradient(100deg, #FFD5DA 0%, #FFFFFF 42%, #FF6B7A 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 0 26px rgba(255, 59, 71, .5));
}

.hero-subtitle {
  font-size: 16px;
  font-size: clamp(15px, 1.4vw, 17px);
  color: rgba(255, 255, 255, .72);
  line-height: 2;
  margin-bottom: 42px;
}

.hero-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: center;
}

.hero-stats {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0;
  margin-top: 60px;
  border-top: 1px solid rgba(255, 255, 255, .12);
  padding-top: 34px;
}

.hero-stats li {
  flex: 1 1 0;
  min-width: 130px;
  padding: 0 22px;
  position: relative;
}

.hero-stats li + li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background: rgba(255, 255, 255, .12);
}

.hero-stats strong {
  display: block;
  white-space: nowrap;
  font-family: Georgia, "Songti SC", serif;
  font-size: 1.7rem;
  font-size: clamp(1.4rem, 2.6vw, 1.9rem);
  line-height: 1.3;
  background: linear-gradient(180deg, #FFFFFF 0%, #FFB3BE 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

.hero-stats span {
  font-size: 13.5px;
  color: rgba(255, 255, 255, .58);
  letter-spacing: .08em;
}

.hero-scroll-indicator {
  position: absolute;
  left: 50%;
  bottom: 32px;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  font-size: 12px;
  letter-spacing: .2em;
  color: rgba(255, 255, 255, .45);
  z-index: 2;
}

.hero-scroll-indicator i {
  width: 22px;
  height: 34px;
  border: 1.5px solid rgba(255, 255, 255, .3);
  border-radius: 9999px;
  position: relative;
}

.hero-scroll-indicator i::after {
  content: "";
  position: absolute;
  top: 7px;
  left: 50%;
  width: 3px;
  height: 6px;
  border-radius: 3px;
  background: var(--c-hl-2);
  box-shadow: 0 0 10px rgba(255, 59, 71, .9);
  transform: translateX(-50%);
  animation: scrollDot 1.8s ease-in-out infinite;
}

@keyframes scrollDot {
  0% { opacity: 0; transform: translate(-50%, 0); }
  35% { opacity: 1; }
  100% { opacity: 0; transform: translate(-50%, 12px); }
}

/* ================================================
   通用 Section
   ================================================ */
.section {
  padding: 100px 0;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 62px;
}

.section-label {
  display: inline-block;
  margin-bottom: 16px;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  background: rgba(255, 59, 71, .12);
  border: 1px solid rgba(255, 59, 71, .28);
  color: #FF8A93;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .18em;
}

.section-title {
  font-size: 2rem;
  font-size: clamp(1.65rem, 3.2vw, 2.4rem);
  margin-bottom: 18px;
  color: #FFFFFF;
}

.section-desc {
  color: rgba(255, 255, 255, .62);
  font-size: 16px;
}

/* ================================================
   平台特色 Features
   ================================================ */
.features { background: var(--c-bg); }

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

.feature-card {
  position: relative;
  padding: 38px 32px;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: transform var(--t-normal), box-shadow var(--t-normal), border-color var(--t-normal), background var(--t-normal);
}

.feature-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, #FF4A54, #FF6B7A);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--t-normal);
}

.feature-card::after {
  content: "";
  position: absolute;
  top: -60px;
  right: -60px;
  width: 160px;
  height: 160px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 59, 71, .22), transparent 70%);
  opacity: 0;
  transition: opacity var(--t-normal);
  pointer-events: none;
}

.feature-card:hover {
  transform: translateY(-6px);
  background: var(--c-surface-hover);
  border-color: rgba(255, 59, 71, .42);
  box-shadow: 0 22px 54px rgba(255, 45, 60, .24);
}

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

.feature-icon {
  width: 58px;
  height: 58px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
  border-radius: 17px;
  background: linear-gradient(140deg, rgba(255, 59, 71, .26), rgba(255, 59, 71, .06));
  border: 1px solid rgba(255, 59, 71, .26);
  color: #FF7A85;
  box-shadow: 0 8px 22px rgba(255, 45, 60, .18);
}

.feature-icon .icon { width: 26px; height: 26px; }

.feature-card h3 {
  font-size: 19px;
  margin-bottom: 12px;
  color: #FFFFFF;
}

.feature-card p {
  font-size: 15px;
  color: rgba(255, 255, 255, .62);
  line-height: 1.85;
}

/* ================================================
   界面预览 Screenshots
   ================================================ */
.screenshots {
  background:
    radial-gradient(760px 400px at 50% 0%, rgba(255, 59, 71, .12) 0%, rgba(255, 59, 71, 0) 62%),
    var(--c-bg-alt);
  border-top: 1px solid rgba(255, 255, 255, .06);
  border-bottom: 1px solid rgba(255, 255, 255, .06);
}

.screenshots-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.screenshot-item {
  position: relative;
  border-radius: var(--radius-md);
  overflow: hidden;
  background: linear-gradient(160deg, #1D0D12, #10080A);
  border: 1px solid var(--c-border);
  box-shadow: 0 14px 38px rgba(0, 0, 0, .55);
  cursor: zoom-in;
  aspect-ratio: 9 / 16;
  transition: transform var(--t-normal), box-shadow var(--t-normal), border-color var(--t-normal);
}

.screenshot-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
  transition: transform var(--t-slow);
}

.screenshot-item:hover {
  transform: translateY(-6px);
  border-color: rgba(255, 59, 71, .5);
  box-shadow: 0 24px 60px rgba(255, 45, 60, .3);
}

.screenshot-item:hover img { transform: scale(1.04); }

.screenshot-caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 26px 16px 14px;
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: .06em;
  color: #FFFFFF;
  background: linear-gradient(to top, rgba(8, 4, 5, .94), rgba(8, 4, 5, 0));
  text-align: center;
}

/* 模态框 */
.modal {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 20px;
  background: rgba(6, 3, 4, .95);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--t-normal), visibility var(--t-normal);
}

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

.modal-content {
  position: relative;
  width: 100%;
  max-width: 420px;
  max-height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-content img {
  max-width: 100%;
  max-height: 80vh;
  width: auto;
  border-radius: var(--radius-md);
  box-shadow: 0 24px 70px rgba(255, 45, 60, .35);
  background: #FFFFFF;
}

.modal-close {
  position: absolute;
  top: -14px;
  right: -14px;
  width: 42px;
  height: 42px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  border-radius: 50%;
  background: linear-gradient(135deg, #FF4A54, #C00E24);
  color: #FFFFFF;
  cursor: pointer;
  box-shadow: var(--glow-sm);
  transition: transform var(--t-fast);
  z-index: 3;
}

.modal-close:hover { transform: rotate(90deg); }

.modal-nav {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  pointer-events: none;
}

.modal-prev,
.modal-next {
  pointer-events: auto;
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(255, 255, 255, .22);
  border-radius: 50%;
  background: rgba(255, 255, 255, .1);
  color: #FFFFFF;
  cursor: pointer;
  transition: background var(--t-fast), transform var(--t-fast);
}

.modal-prev:hover,
.modal-next:hover { background: rgba(255, 59, 71, .45); transform: scale(1.06); }

.modal-prev .icon,
.modal-next .icon { width: 24px; height: 24px; }

/* ================================================
   使用指南 Guide
   ================================================ */
.guide { background: var(--c-bg); }

.timeline {
  position: relative;
  max-width: 860px;
  margin: 0 auto;
  padding-left: 34px;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(to bottom, #FF4A54, rgba(255, 59, 71, .35), transparent);
  box-shadow: 0 0 14px rgba(255, 59, 71, .5);
}

.timeline-item {
  position: relative;
  margin-bottom: 26px;
  padding: 26px 30px;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  transition: transform var(--t-normal), box-shadow var(--t-normal), border-color var(--t-normal), background var(--t-normal);
}

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

.timeline-item::before {
  content: "";
  position: absolute;
  left: -34px;
  top: 32px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--c-bg);
  border: 3px solid var(--c-primary);
  box-shadow: 0 0 0 4px rgba(255, 59, 71, .14), 0 0 16px rgba(255, 59, 71, .6);
}

.timeline-item:hover {
  transform: translateX(6px);
  background: var(--c-surface-hover);
  border-color: rgba(255, 59, 71, .42);
  box-shadow: 0 20px 48px rgba(255, 45, 60, .22);
}

.timeline-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 16px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--c-border);
}

.timeline-version {
  padding: 5px 14px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, #FF4A54, #C00E24);
  color: #FFFFFF;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .08em;
  box-shadow: var(--glow-sm);
}

.timeline-date {
  font-family: Georgia, "Songti SC", serif;
  font-size: 18px;
  font-weight: 700;
  color: #FFFFFF;
}

.timeline-content ul li {
  position: relative;
  padding-left: 22px;
  margin-bottom: 10px;
  font-size: 15px;
  color: rgba(255, 255, 255, .66);
  line-height: 1.8;
}

.timeline-content ul li:last-child { margin-bottom: 0; }

.timeline-content ul li i {
  position: absolute;
  left: 0;
  top: 11px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--c-primary);
  box-shadow: 0 0 10px rgba(255, 59, 71, .8);
}

/* ================================================
   关于 About
   ================================================ */
.about {
  background:
    radial-gradient(700px 380px at 82% 12%, rgba(255, 59, 71, .12) 0%, rgba(255, 59, 71, 0) 62%),
    var(--c-bg-alt);
  border-top: 1px solid rgba(255, 255, 255, .06);
}

.about-content {
  display: grid;
  grid-template-columns: 1.15fr .85fr;
  gap: 56px;
  align-items: center;
}

.about-text h3 {
  font-size: 24px;
  margin-bottom: 20px;
  color: #FFFFFF;
}

.about-text p {
  font-size: 15.5px;
  color: rgba(255, 255, 255, .66);
  line-height: 1.95;
  margin-bottom: 16px;
}

.about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 30px;
}

.about-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.about-stat {
  padding: 30px 24px;
  text-align: center;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  transition: transform var(--t-normal), box-shadow var(--t-normal), border-color var(--t-normal);
}

.about-stat:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 59, 71, .42);
  box-shadow: 0 18px 44px rgba(255, 45, 60, .22);
}

.stat-number {
  white-space: nowrap;
  font-family: Georgia, "Songti SC", serif;
  font-size: 1.8rem;
  font-size: clamp(1.5rem, 2.6vw, 1.95rem);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 6px;
  background: linear-gradient(135deg, #FF6B7A 0%, #FF3B47 55%, #FFB3BE 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

.stat-label {
  font-size: 13.5px;
  color: rgba(255, 255, 255, .5);
  letter-spacing: .08em;
}

/* ================================================
   底部 Footer
   ================================================ */
.footer {
  padding: 64px 0 34px;
  color: #FFFFFF;
  background: linear-gradient(180deg, #0D0809 0%, #070405 100%);
  border-top: 1px solid rgba(255, 255, 255, .07);
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 26px;
  padding-bottom: 34px;
  border-bottom: 1px solid rgba(255, 255, 255, .08);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.footer-brand img {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  background: #FFFFFF;
  object-fit: contain;
  padding: 3px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 26px;
}

.footer-links a {
  font-size: 14.5px;
  color: rgba(255, 255, 255, .62);
  transition: color var(--t-fast);
}

.footer-links a:hover { color: var(--c-hl); }

.footer-bottom {
  padding-top: 26px;
  text-align: center;
}

.footer-bottom p {
  font-size: 13.5px;
  color: rgba(255, 255, 255, .42);
  margin-bottom: 8px;
}

.footer-disclaimer {
  max-width: 780px;
  margin: 0 auto;
  line-height: 1.85;
  font-size: 12.5px !important;
  color: rgba(255, 255, 255, .3) !important;
}

/* ================================================
   返回顶部
   ================================================ */
.back-to-top {
  position: fixed;
  right: 26px;
  bottom: 26px;
  z-index: 900;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  border-radius: 50%;
  background: linear-gradient(135deg, #FF4A54, #C00E24);
  color: #FFFFFF;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(14px);
  box-shadow: var(--glow-md);
  transition: opacity var(--t-normal), visibility var(--t-normal), transform var(--t-normal), box-shadow var(--t-fast);
}

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

.back-to-top:hover {
  transform: translateY(-3px);
  box-shadow: var(--glow-lg);
}

/* ================================================
   响应式
   ================================================ */
@media (max-width: 992px) {
  .section { padding: 84px 0; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .screenshots-grid { grid-template-columns: repeat(3, 1fr); }
  .about-content { grid-template-columns: 1fr; gap: 40px; }
}

@media (max-width: 768px) {
  :root { --nav-height: 64px; }

  .section { padding: 68px 0; }
  .section-header { margin-bottom: 44px; }

  /* 移动端导航抽屉 */
  .nav-toggle { display: block; }

  .nav-menu {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    z-index: 999;
    width: 82vw;
    max-width: 300px;
    /* 用 top/bottom 撑满视口，比 height:100% 更稳，不依赖包含块高度 */
    height: auto;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 4px;
    padding: calc(var(--nav-height) + 24px) 24px calc(28px + env(safe-area-inset-bottom, 0px));
    background: linear-gradient(170deg, #1C0C11 0%, #0B0709 100%);
    box-shadow: -14px 0 44px rgba(0, 0, 0, .6);
    transform: translateX(100%);
    transition: transform var(--t-normal);
    overflow-y: auto;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
  }

  .nav-menu.active { transform: translateX(0); }

  .nav-menu li { width: 100%; }

  .nav-menu a {
    display: block;
    padding: 15px 8px;
    font-size: 16px;
    border-bottom: 1px solid rgba(255, 255, 255, .08);
  }

  .nav-menu a::after { display: none; }

  .nav-cta-item { display: block; margin-top: 22px; }

  .nav-cta-item .btn-nav {
    width: 100%;
    padding: 15px 24px;
    font-size: 16px;
    border-bottom: none;
  }

  /* 移动端：主视觉撑满首屏。内容与「向下滚动」各占一段弹性留白，
     提示符号自然落到底部并始终水平居中；矮屏仍保留最小间距，不会重叠 */
  .hero {
    min-height: 100vh;
    min-height: 100svh;
    padding: calc(var(--nav-height) + 28px) 22px 36px;
  }

  .hero-content {
    margin-top: auto;
    margin-bottom: 0;
  }

  .hero-scroll-indicator {
    position: static;
    top: auto;
    left: auto;
    right: auto;
    bottom: auto;
    transform: none;
    align-self: center;
    margin-top: auto;
    margin-right: auto;
    margin-bottom: 0;
    margin-left: auto;
    padding-top: 64px;
  }

  .hero-subtitle { margin-bottom: 34px; }
  .hero-stats { margin-top: 34px; padding-top: 26px; }
  .hero-stats li { min-width: 100px; padding: 0 12px; }

  .features-grid { grid-template-columns: 1fr; gap: 18px; }
  .screenshots-grid { grid-template-columns: repeat(2, 1fr); gap: 16px; }
  .about-stats { grid-template-columns: repeat(2, 1fr); }

  .timeline { padding-left: 26px; }
  .timeline-item { padding: 22px 22px; }
  .timeline-item::before { left: -26px; top: 28px; width: 13px; height: 13px; border-width: 3px; }

  .modal-prev, .modal-next { width: 44px; height: 44px; }
}

@media (max-width: 480px) {
  .container { padding: 0 18px; }

  .navbar-logo img { width: 38px; height: 38px; }
  .logo-text { font-size: 18px; }
  .logo-text small { font-size: 10px; letter-spacing: .12em; }

  .hero-title { font-size: 1.85rem; }
  .hero-buttons { flex-direction: column; }
  .hero-buttons .btn { width: 100%; }
  .hero-stats li { min-width: 0; flex: 1 1 30%; padding: 0 8px; }
  .hero-stats strong { font-size: 1.15rem; }
  .hero-stats span { font-size: 12px; }

  .screenshots-grid { gap: 14px; }
  .about-stats { grid-template-columns: 1fr; }
  .about-actions .btn { width: 100%; }

  .footer-content { flex-direction: column; align-items: flex-start; }
  .footer-links { gap: 16px 22px; }

  .back-to-top { right: 16px; bottom: 16px; width: 44px; height: 44px; }
}