/* =====================================================
   一键学习 官网样式
   风格与小程序保持一致：紫色系 + 圆角卡片 + 活泼渐变
   ===================================================== */

:root {
  --primary: #6C5CE7;
  --primary-deep: #5A4BD1;
  --primary-soft: #EFEBFF;
  --pink: #FF7BAC;
  --cyan: #59D5E8;
  --orange: #FFA94D;
  --red: #FF6B6B;
  --blue: #4D96FF;
  --text: #2B2B3C;
  --text-sub: #6B6B80;
  --muted: #9A9AB0;
  --bg: #FFFFFF;
  --bg-soft: #F5F2FF;
  --border: #ECE8FA;
  --radius-lg: 24px;
  --radius-md: 16px;
  --shadow-card: 0 10px 30px rgba(108, 92, 231, 0.10);
  --shadow-phone: 0 18px 44px rgba(108, 92, 231, 0.18);
  --header-h: 72px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Segoe UI", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

a { color: inherit; text-decoration: none; }

ul, ol { list-style: none; }

.container {
  width: min(1140px, 92%);
  margin: 0 auto;
}

/* ---------------- 通用按钮 ---------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 600;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: linear-gradient(135deg, #8B7BFF 0%, var(--primary) 100%);
  color: #fff;
  box-shadow: 0 8px 20px rgba(108, 92, 231, .35);
}

.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 26px rgba(108, 92, 231, .42); }

.btn-ghost {
  background: #fff;
  color: var(--primary);
  border: 2px solid var(--primary-soft);
}

.btn-ghost:hover { border-color: var(--primary); transform: translateY(-2px); }

.btn-lg { padding: 15px 34px; font-size: 16px; }

/* ---------------- 顶部导航 ---------------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  background: rgba(255, 255, 255, .85);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  transition: box-shadow .25s ease;
}

.site-header.scrolled { box-shadow: 0 6px 24px rgba(108, 92, 231, .08); }

.header-inner {
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand { display: flex; align-items: center; gap: 10px; }

.brand-logo { display: inline-flex; }

.brand-name {
  font-size: 20px;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: 1px;
}

.main-nav { display: flex; gap: 6px; }

.nav-link {
  padding: 8px 16px;
  border-radius: 999px;
  font-size: 15px;
  color: var(--text-sub);
  font-weight: 500;
  transition: color .2s, background .2s;
}

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

.nav-link.active { color: var(--primary); background: var(--primary-soft); font-weight: 700; }

.header-cta { padding: 10px 22px; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: 8px;
  cursor: pointer;
}

.nav-toggle span {
  width: 24px; height: 2.5px;
  background: var(--primary);
  border-radius: 2px;
  transition: transform .25s ease, opacity .25s ease;
}

/* ---------------- Hero 首屏 ---------------- */
.hero {
  position: relative;
  padding: calc(var(--header-h) + 70px) 0 90px;
  background: linear-gradient(180deg, #F3EFFF 0%, #FBFAFF 70%, #fff 100%);
  overflow: hidden;
}

.hero-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(70px);
  opacity: .55;
  pointer-events: none;
}

.blob-1 { width: 420px; height: 420px; background: #D9CFFF; top: -120px; left: -120px; }
.blob-2 { width: 360px; height: 360px; background: #FFD9EA; bottom: -140px; right: -80px; }
.blob-3 { width: 260px; height: 260px; background: #D2F6FB; top: 30%; right: 28%; opacity: .4; }

.hero-inner {
  position: relative;
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  align-items: center;
  gap: 48px;
}

.hero-badge {
  display: inline-block;
  padding: 7px 18px;
  border-radius: 999px;
  background: #fff;
  border: 1.5px solid var(--border);
  color: var(--primary);
  font-size: 14px;
  font-weight: 600;
  box-shadow: 0 4px 14px rgba(108, 92, 231, .08);
  margin-bottom: 22px;
}

.hero-title { margin-bottom: 18px; }

.hero-title .formula {
  display: block;
  font-size: clamp(34px, 5vw, 54px);
  font-weight: 900;
  line-height: 1.2;
  background: linear-gradient(120deg, #6C5CE7 10%, #A66CFF 55%, #FF7BAC 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: 1px;
}

.hero-title .formula sup { font-size: .45em; -webkit-text-fill-color: var(--pink); }

.hero-title .slogan {
  display: block;
  font-size: clamp(26px, 3.6vw, 38px);
  font-weight: 800;
  margin-top: 6px;
}

.hero-desc {
  font-size: 16.5px;
  color: var(--text-sub);
  max-width: 520px;
  margin-bottom: 30px;
}

.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 38px; }

.hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 38px;
}

.hero-stats li { display: flex; flex-direction: column; }

.hero-stats strong {
  font-size: 24px;
  font-weight: 800;
  color: var(--primary);
}

.hero-stats span { font-size: 13px; color: var(--muted); }

/* 首屏手机模型 */
.hero-phone { position: relative; display: flex; justify-content: center; }

.phone {
  width: min(280px, 78vw);
  background: #1E1B2E;
  border-radius: 36px;
  padding: 10px;
  box-shadow: var(--shadow-phone);
  position: relative;
}

.phone img {
  border-radius: 28px;
  width: 100%;
  aspect-ratio: 390 / 844;
  object-fit: cover;
  background: #fff;
}

.phone-notch {
  position: absolute;
  top: 16px; left: 50%;
  transform: translateX(-50%);
  width: 84px; height: 8px;
  background: rgba(255,255,255,.85);
  border-radius: 999px;
  z-index: 2;
}

.phone-sm { width: 100%; padding: 7px; border-radius: 26px; }
.phone-sm img { border-radius: 20px; aspect-ratio: 390 / 844; }

.hero-float {
  position: absolute;
  background: #fff;
  border-radius: 14px;
  padding: 10px 16px;
  font-size: 13.5px;
  font-weight: 700;
  color: var(--primary);
  box-shadow: var(--shadow-card);
  animation: float 4s ease-in-out infinite;
  white-space: nowrap;
}

.f1 { top: 12%; left: -4%; }
.f2 { top: 46%; right: -8%; animation-delay: 1.2s; color: var(--red); }
.f3 { bottom: 6%; left: 2%; animation-delay: 2.2s; color: var(--orange); }

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

/* ---------------- 通用 Section ---------------- */
.section { padding: 90px 0; }

.section-head { text-align: center; margin-bottom: 52px; }

.section-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--pink);
  margin-bottom: 10px;
}

.section-title { font-size: clamp(26px, 3.4vw, 36px); font-weight: 800; }

.section-sub { color: var(--text-sub); margin-top: 12px; font-size: 16px; }

/* ---------------- 功能卡片 ---------------- */
.features { background: var(--bg-soft); }

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: #fff;
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  transition: transform .25s ease, box-shadow .25s ease;
}

.feature-card:hover { transform: translateY(-6px); box-shadow: 0 18px 40px rgba(108, 92, 231, .16); }

.feature-icon {
  width: 56px; height: 56px;
  border-radius: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

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

.i-purple { background: var(--primary-soft); color: var(--primary); }
.i-pink   { background: #FFE9F2; color: var(--pink); }
.i-cyan   { background: #E2F8FB; color: #17B3C9; }
.i-orange { background: #FFF1E0; color: var(--orange); }
.i-red    { background: #FFE7E7; color: var(--red); }
.i-blue   { background: #E6F0FF; color: var(--blue); }

.feature-card h3 { font-size: 19px; margin-bottom: 10px; }

.feature-card p { font-size: 14.5px; color: var(--text-sub); }

/* ---------------- 产品截图预览 ---------------- */
.shot-tabs {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-bottom: 44px;
  flex-wrap: wrap;
}

.shot-tab {
  padding: 10px 28px;
  border-radius: 999px;
  border: 1.5px solid var(--border);
  background: #fff;
  color: var(--text-sub);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: all .2s ease;
}

.shot-tab:hover { color: var(--primary); border-color: var(--primary); }

.shot-tab.active {
  background: linear-gradient(135deg, #8B7BFF, var(--primary));
  color: #fff;
  border-color: transparent;
  box-shadow: 0 8px 18px rgba(108, 92, 231, .3);
}

.shot-panels { position: relative; }

.shot-panel {
  display: none;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
}

.shot-panel.active { display: flex; animation: fadeIn .4s ease; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: none; } }

.phone-item { text-align: center; }

.phone-item .phone { width: min(260px, 80vw); }

.phone-item figcaption {
  margin-top: 16px;
  font-size: 15px;
  font-weight: 700;
  color: var(--text-sub);
}

/* ---------------- 新手引导流程 ---------------- */
.guide-flow {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 22px;
  counter-reset: step;
}

.guide-step {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px 20px 20px;
  text-align: center;
  box-shadow: var(--shadow-card);
  position: relative;
  transition: transform .25s ease;
}

.guide-step:hover { transform: translateY(-6px); }

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px; height: 38px;
  border-radius: 50%;
  background: linear-gradient(135deg, #8B7BFF, var(--primary));
  color: #fff;
  font-weight: 800;
  font-size: 17px;
  margin-bottom: 14px;
  box-shadow: 0 6px 14px rgba(108, 92, 231, .35);
}

.guide-step h3 { font-size: 17px; margin-bottom: 6px; }

.guide-step p {
  font-size: 13px;
  color: var(--text-sub);
  min-height: 66px;
}

.guide-step .phone {
  box-shadow: 0 10px 24px rgba(108, 92, 231, .14);
}

/* ---------------- 关于我们 ---------------- */
.about { background: var(--bg-soft); }

.about-inner {
  display: grid;
  grid-template-columns: 1.2fr .8fr;
  gap: 48px;
  align-items: start;
}

.about-copy .section-title { margin-bottom: 20px; }

.about-copy p { color: var(--text-sub); margin-bottom: 14px; font-size: 15.5px; }

.about-points { margin-top: 22px; display: grid; gap: 10px; }

.about-points li {
  font-size: 15px;
  font-weight: 600;
  color: var(--primary);
}

.about-card {
  background: #fff;
  border-radius: var(--radius-lg);
  padding: 34px 30px;
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
}

.about-card h3 { font-size: 20px; margin-bottom: 20px; }

.contact-list { display: grid; gap: 16px; margin-bottom: 20px; }

.contact-list li {
  display: flex;
  gap: 14px;
  font-size: 14.5px;
  align-items: baseline;
}

.c-label {
  flex-shrink: 0;
  padding: 3px 12px;
  border-radius: 999px;
  background: var(--primary-soft);
  color: var(--primary);
  font-size: 12.5px;
  font-weight: 700;
}

.about-note { font-size: 13px; color: var(--muted); }

/* ---------------- 页脚 ---------------- */
.site-footer {
  background: #241E45;
  color: #CFC9EE;
  padding: 56px 0 30px;
  font-size: 14px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 30px;
  flex-wrap: wrap;
  padding-bottom: 34px;
  border-bottom: 1px solid rgba(255,255,255,.12);
}

.footer-brand .brand-name { color: #fff; font-size: 22px; }

.footer-brand p { margin-top: 10px; color: #A79FD4; }

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

.footer-nav a { color: #CFC9EE; transition: color .2s; }

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

.footer-beian {
  padding-top: 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: center;
  text-align: center;
}

.copyright { color: #8F87C2; font-size: 13px; }

.beian-links {
  display: flex;
  gap: 22px;
  flex-wrap: wrap;
  justify-content: center;
}

.beian-links a {
  color: #CFC9EE;
  font-size: 13px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: color .2s;
}

.beian-links a:hover { color: #fff; }

.beian-pending { color: #8F87C2; font-size: 13px; }

/* ---------------- 滚动入场动画 ---------------- */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity .7s ease, transform .7s ease;
}

.reveal.visible { opacity: 1; transform: none; }

.delay-1 { transition-delay: .12s; }
.delay-2 { transition-delay: .24s; }

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .hero-float { animation: none; }
  html { scroll-behavior: auto; }
}

/* =====================================================
   响应式适配
   ===================================================== */
@media (max-width: 1024px) {
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .guide-flow { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 860px) {
  .main-nav {
    position: fixed;
    top: var(--header-h);
    left: 0; right: 0;
    background: #fff;
    flex-direction: column;
    padding: 16px 6%;
    gap: 4px;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 16px 30px rgba(108, 92, 231, .10);
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: transform .25s ease, opacity .25s ease, visibility .25s;
  }

  .main-nav.open { transform: none; opacity: 1; visibility: visible; }

  .nav-link { padding: 13px 16px; border-radius: 12px; font-size: 16px; }

  .header-cta { display: none; }

  .nav-toggle { display: flex; }

  .nav-toggle.open span:nth-child(1) { transform: translateY(7.5px) rotate(45deg); }
  .nav-toggle.open span:nth-child(2) { opacity: 0; }
  .nav-toggle.open span:nth-child(3) { transform: translateY(-7.5px) rotate(-45deg); }

  .hero { padding-top: calc(var(--header-h) + 44px); }

  .hero-inner { grid-template-columns: 1fr; gap: 52px; text-align: center; }

  .hero-desc { margin-left: auto; margin-right: auto; }

  .hero-actions, .hero-stats { justify-content: center; }

  .about-inner { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .section { padding: 64px 0; }

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

  .guide-flow { grid-template-columns: 1fr 1fr; gap: 16px; }

  .hero-float { display: none; }

  .shot-panel { gap: 28px; }

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

@media (max-width: 420px) {
  .guide-flow { grid-template-columns: 1fr; }
  .guide-step p { min-height: 0; }
}