/* StudyBar 推广落地页 —— Apple 简约深色风，配色对齐软件主题 */

:root {
  --bg: #0E0E10;
  --bg-alt: #16161A;
  --card: #2C2C2E;
  --card-2: #232326;
  --line: rgba(255, 255, 255, .10);
  --accent: #FFD700;
  --accent-2: #5E5CE6;
  --text: #FFFFFF;
  --sub: #A1A1A6;
  --dim: #8E8E93;
  --green: #30D158;
  --radius: 16px;
  --wrap: 1180px;
}

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

html { scroll-behavior: smooth; }

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

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
code {
  background: rgba(255, 255, 255, .08);
  padding: 2px 6px;
  border-radius: 5px;
  font-size: .9em;
  font-family: "Cascadia Code", Consolas, Monaco, monospace;
}

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 24px; }
.wrap-narrow { max-width: 820px; }

.hl { color: var(--accent); }

/* ───── 按钮 ───── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 26px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 15px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
  white-space: nowrap;
}
.btn-primary {
  background: var(--accent);
  color: #1C1C1E;
  box-shadow: 0 6px 22px rgba(255, 215, 0, .22);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 30px rgba(255, 215, 0, .34);
}
.btn-ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--line);
}
.btn-ghost:hover {
  background: rgba(255, 255, 255, .06);
  transform: translateY(-2px);
}
.btn-sm { padding: 9px 18px; font-size: 14px; }
.btn-lg { padding: 16px 40px; font-size: 17px; }

/* ───── 导航 ───── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(14, 14, 16, .82);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 62px;
  gap: 20px;
}
.brand { display: flex; align-items: baseline; gap: 8px; font-weight: 700; font-size: 19px; }
.brand-icon { font-size: 21px; }
.brand-ver {
  font-size: 11px;
  color: var(--dim);
  font-weight: 500;
  border: 1px solid var(--line);
  padding: 1px 7px;
  border-radius: 999px;
}
.nav-links { display: flex; gap: 28px; }
.nav-links a {
  font-size: 14.5px;
  color: var(--sub);
  transition: color .18s ease;
}
.nav-links a:hover { color: var(--accent); }

/* ───── Hero ───── */
.hero {
  padding: 76px 0 90px;
  background:
    radial-gradient(900px 460px at 72% 8%, rgba(255, 215, 0, .10), transparent 62%),
    radial-gradient(760px 420px at 12% 26%, rgba(94, 92, 230, .14), transparent 60%);
}
.hero-inner {
  display: grid;
  grid-template-columns: 1.04fr 1fr;
  gap: 56px;
  align-items: center;
}
.badge {
  display: inline-block;
  font-size: 13px;
  color: var(--accent);
  background: rgba(255, 215, 0, .10);
  border: 1px solid rgba(255, 215, 0, .28);
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 22px;
}
.hero h1 {
  font-size: 52px;
  line-height: 1.18;
  letter-spacing: -.5px;
  font-weight: 800;
  margin-bottom: 20px;
}
.hero-sub {
  font-size: 17px;
  color: var(--sub);
  max-width: 560px;
  margin-bottom: 30px;
}
.hero-sub strong { color: var(--text); }
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 22px; }
.hero-tips { list-style: none; display: flex; flex-direction: column; gap: 7px; }
.hero-tips li { font-size: 14px; color: var(--dim); }

/* 仿真窗口 */
.mock {
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: 14px;
  overflow: hidden;
  box-shadow: 0 28px 70px rgba(0, 0, 0, .55);
}
.mock-bar {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 11px 14px;
  background: rgba(255, 255, 255, .04);
  border-bottom: 1px solid var(--line);
}
.dot { width: 11px; height: 11px; border-radius: 50%; display: inline-block; }
.dot-r { background: #FF5F57; }
.dot-y { background: #FEBC2E; }
.dot-g { background: #28C840; }
.mock-title {
  margin-left: 12px;
  font-size: 12px;
  color: var(--dim);
}
.mock-screen {
  position: relative;
  height: 330px;
  padding: 26px 26px;
  background: linear-gradient(160deg, #1F1F23 0%, #17171A 100%);
}
.skeleton { margin-top: 96px; }
.sk-line {
  height: 11px;
  border-radius: 6px;
  background: rgba(255, 255, 255, .07);
  margin-bottom: 14px;
}
.sk-block {
  height: 74px;
  border-radius: 10px;
  background: rgba(255, 255, 255, .05);
  margin: 18px 0;
}
.w70 { width: 70%; }
.w60 { width: 60%; }
.w50 { width: 50%; }
.w40 { width: 40%; }

/* 顶部学习条 */
.bar {
  position: absolute;
  left: 50%;
  top: 16px;
  transform: translateX(-50%);
  width: 92%;
  background: rgba(28, 28, 30, .96);
  border: 1px solid rgba(255, 255, 255, .10);
  border-radius: 12px;
  box-shadow: 0 14px 42px rgba(0, 0, 0, .5);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  overflow: hidden;
  animation: barFloat 4s ease-in-out infinite;
}
@keyframes barFloat {
  0%, 100% { opacity: 1; }
  50% { box-shadow: 0 18px 52px rgba(0, 0, 0, .6); }
}
.bar-body {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 18px 12px;
}
.bar-icon { font-size: 24px; }
.bar-text { flex: 1; min-width: 0; }
.bar-main {
  font-size: 16px;
  font-weight: 700;
  color: #FFFFFF;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.caret {
  color: var(--accent);
  animation: blink 1s steps(1) infinite;
  font-weight: 400;
}
@keyframes blink { 50% { opacity: 0; } }
.bar-sub {
  font-size: 12.5px;
  color: var(--dim);
  margin-top: 3px;
  min-height: 18px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  opacity: 0;
  transition: opacity .5s ease;
}
.bar-sub.show { opacity: 1; }
.bar-right { display: flex; flex-direction: column; align-items: flex-end; gap: 4px; }
.bar-idx {
  font-size: 11px;
  color: var(--accent-2);
  font-weight: 600;
}
.bar-nav { display: flex; gap: 8px; font-size: 11px; color: var(--dim); }
.bar-prog {
  position: relative;
  height: 8px;
  background: rgba(255, 255, 255, .10);
}
.bar-prog-fill {
  height: 2px;
  background: var(--accent);
  position: absolute;
  top: 3px;
  left: 0;
  width: 0;
  transition: width .45s ease;
}
.bar-prog-knob {
  position: absolute;
  top: 0;
  left: 0;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  transform: translateX(-4px);
  transition: left .45s ease;
}
.demo-cap {
  text-align: center;
  font-size: 12.5px;
  color: var(--dim);
  margin-top: 14px;
}

/* ───── 区块通用 ───── */
.section { padding: 92px 0; }
.section-alt { background: var(--bg-alt); }
.sec-head { text-align: center; margin-bottom: 52px; }
.sec-head h2 {
  font-size: 36px;
  font-weight: 800;
  letter-spacing: -.3px;
  margin-bottom: 14px;
}
.sec-desc {
  color: var(--sub);
  font-size: 16.5px;
  max-width: 720px;
  margin: 0 auto;
}
.sec-desc strong { color: var(--text); }

/* 痛点 */
.pain-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
  margin-bottom: 54px;
}
.pain-card {
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 26px;
  text-align: center;
  transition: transform .2s ease, border-color .2s ease;
}
.pain-card:hover { transform: translateY(-4px); border-color: rgba(255, 215, 0, .3); }
.pain-icon { font-size: 30px; margin-bottom: 12px; }
.pain-card h3 { font-size: 18px; margin-bottom: 10px; }
.pain-card p { color: var(--sub); font-size: 14.5px; }
.pain-card strong { color: var(--accent); }

/* 循环流程 */
.loop {
  display: flex;
  align-items: stretch;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}
.loop-step {
  flex: 1 1 200px;
  max-width: 250px;
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 22px 20px;
  text-align: center;
}
.loop-step-hl { border-color: rgba(255, 215, 0, .42); background: rgba(255, 215, 0, .07); }
.loop-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: rgba(255, 215, 0, .16);
  color: var(--accent);
  font-weight: 700;
  margin-bottom: 10px;
}
.loop-step h4 { font-size: 16px; margin-bottom: 6px; }
.loop-step p { font-size: 13.5px; color: var(--sub); }
.loop-arrow {
  display: flex;
  align-items: center;
  color: var(--dim);
  font-size: 20px;
}

/* 功能 */
.feat-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}
.feat-card {
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 26px;
  transition: transform .2s ease, border-color .2s ease, background .2s ease;
}
.feat-card:hover {
  transform: translateY(-5px);
  border-color: rgba(255, 215, 0, .34);
  background: rgba(255, 215, 0, .04);
}
.feat-icon { font-size: 28px; margin-bottom: 14px; }
.feat-card h3 { font-size: 18.5px; margin-bottom: 10px; }
.feat-card p { color: var(--sub); font-size: 14.5px; }
.feat-card strong { color: var(--accent); }
/* 「规划中 / 考虑增加」标签 */
.soon {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  color: var(--dim);
  border: 1px dashed rgba(255, 255, 255, .32);
  border-radius: 999px;
  padding: 1px 9px;
  vertical-align: middle;
  white-space: nowrap;
}

/* 词库 */
.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin-bottom: 30px;
}
.chip {
  padding: 7px 16px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--sub);
  font-size: 14px;
  cursor: pointer;
  transition: all .18s ease;
  font-family: inherit;
}
.chip:hover { color: var(--text); border-color: rgba(255, 215, 0, .4); }
.chip.active {
  background: var(--accent);
  color: #1C1C1E;
  border-color: var(--accent);
  font-weight: 600;
}
.lib-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}
.lib-card {
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 16px 16px 14px;
  transition: transform .18s ease, border-color .18s ease;
}
.lib-card:hover { transform: translateY(-3px); border-color: rgba(255, 215, 0, .34); }
.lib-cat {
  display: inline-block;
  font-size: 11px;
  color: var(--dim);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 1px 8px;
  margin-bottom: 9px;
}
.lib-name {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}
.lib-free {
  font-size: 10.5px;
  color: var(--green);
  border: 1px solid rgba(48, 209, 88, .4);
  background: rgba(48, 209, 88, .10);
  border-radius: 999px;
  padding: 0 7px;
  font-weight: 600;
  white-space: nowrap;
}
.lib-desc {
  font-size: 12.5px;
  color: var(--dim);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.lib-more { text-align: center; margin-top: 30px; }

/* 价格 */
.price-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 16px;
  align-items: stretch;
}
.price-card {
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 20px;
  text-align: center;
  position: relative;
  transition: transform .2s ease;
  display: flex;
  flex-direction: column;
}
.price-card:hover { transform: translateY(-4px); }
.price-hot {
  border-color: var(--accent);
  background: rgba(255, 215, 0, .07);
  box-shadow: 0 10px 34px rgba(255, 215, 0, .16);
}
.price-tag {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent);
  color: #1C1C1E;
  font-size: 12px;
  font-weight: 700;
  padding: 3px 14px;
  border-radius: 999px;
  white-space: nowrap;
}
.price-name { font-size: 15px; color: var(--sub); margin-bottom: 10px; }
.price-val {
  font-size: 38px;
  font-weight: 800;
  color: var(--accent);
  line-height: 1.1;
  margin-bottom: 8px;
}
.price-per { font-size: 12.5px; color: var(--dim); margin-bottom: 16px; }
.price-list {
  list-style: none;
  font-size: 13px;
  color: var(--sub);
  margin-bottom: 14px;
  flex: 1;
}
.price-list li { padding: 3px 0; }
.price-list li::before { content: "✓ "; color: var(--green); }
.price-note {
  font-size: 12px;
  color: var(--dim);
  border-top: 1px solid var(--line);
  padding-top: 12px;
}
.price-foot {
  margin-top: 34px;
  background: rgba(48, 209, 88, .07);
  border: 1px solid rgba(48, 209, 88, .26);
  border-radius: 14px;
  padding: 20px 26px;
  text-align: center;
  font-size: 15px;
  color: var(--sub);
}
.price-foot strong { color: var(--green); }

/* 步骤 */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}
.step {
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 26px;
  text-align: center;
}
.step-num {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--accent);
  color: #1C1C1E;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 14px;
}
.step h3 { font-size: 18px; margin-bottom: 8px; }
.step p { color: var(--sub); font-size: 14.5px; }

/* FAQ */
.faq { display: flex; flex-direction: column; gap: 12px; }
.faq-item {
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
}
.faq-q {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  color: var(--text);
  font-size: 16px;
  font-weight: 600;
  padding: 18px 22px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  font-family: inherit;
  transition: background .18s ease;
}
.faq-q:hover { background: rgba(255, 255, 255, .04); }
.faq-arrow { color: var(--accent); font-size: 19px; font-weight: 400; flex-shrink: 0; }
.faq-item.open .faq-arrow { transform: rotate(45deg); }
.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height .3s ease;
}
.faq-item.open .faq-a { max-height: 320px; }
.faq-a p { padding: 0 22px 20px; color: var(--sub); font-size: 14.5px; }
.faq-a strong { color: var(--text); }

/* 下载 */
.download-sec { padding-bottom: 60px; }
.dl-card {
  background: linear-gradient(150deg, rgba(255, 215, 0, .10), rgba(94, 92, 230, .10));
  border: 1px solid rgba(255, 215, 0, .26);
  border-radius: 22px;
  padding: 54px 30px;
  text-align: center;
}
.dl-card h2 { font-size: 32px; font-weight: 800; margin-bottom: 12px; }
.dl-sub { color: var(--sub); margin-bottom: 26px; font-size: 16px; }
.dl-tip { color: var(--dim); font-size: 13.5px; margin-top: 18px; }

/* QQ 群 */
.qq-card {
  display: flex;
  align-items: center;
  gap: 36px;
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 34px;
}
.qq-img {
  flex-shrink: 0;
  width: 168px;
  height: 168px;
  background: #fff;
  border-radius: 14px;
  padding: 8px;
}
.qq-img img { width: 100%; height: 100%; object-fit: contain; border-radius: 8px; }
.qq-text h2 { font-size: 26px; margin-bottom: 8px; }
.qq-num { font-size: 17px; color: var(--sub); margin-bottom: 12px; }
.qq-num strong { color: var(--accent); font-size: 20px; }
.qq-text p { color: var(--sub); font-size: 15px; }

/* 页脚 */
.footer {
  padding: 44px 0;
  border-top: 1px solid var(--line);
  text-align: center;
  background: var(--bg);
}
.foot-brand { font-size: 19px; font-weight: 700; margin-bottom: 10px; }
.foot-ver {
  font-size: 11px;
  color: var(--dim);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 1px 7px;
  margin-left: 6px;
  vertical-align: middle;
}
.foot-slogan { color: var(--sub); font-size: 14.5px; margin-bottom: 8px; }
.foot-meta { color: var(--dim); font-size: 13px; }

/* 滚动淡入 */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .6s ease, transform .6s ease;
}
.reveal.in { opacity: 1; transform: none; }

/* ───── 响应式 ───── */
@media (max-width: 1024px) {
  .hero-inner { grid-template-columns: 1fr; gap: 42px; }
  .hero h1 { font-size: 42px; }
  .price-grid { grid-template-columns: repeat(3, 1fr); }
  .lib-grid { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 820px) {
  .nav-links { display: none; }
  .section { padding: 66px 0; }
  .sec-head h2 { font-size: 28px; }
  .pain-grid, .feat-grid, .steps { grid-template-columns: repeat(2, 1fr); }
  .price-grid { grid-template-columns: repeat(2, 1fr); gap: 14px; }
  .lib-grid { grid-template-columns: repeat(2, 1fr); }
  .qq-card { flex-direction: column; text-align: center; gap: 22px; }
  .loop-arrow { transform: rotate(90deg); }
  .hero { padding: 52px 0 66px; }
  .hero h1 { font-size: 34px; }
  .dl-card { padding: 40px 20px; }
  .dl-card h2 { font-size: 25px; }
}

@media (max-width: 560px) {
  .pain-grid, .feat-grid, .steps, .price-grid, .lib-grid { grid-template-columns: 1fr; }
  .hero-cta .btn { width: 100%; }
  .mock-screen { height: 290px; padding: 18px; }
  .bar-body { padding: 12px 14px 10px; gap: 10px; }
  .bar-main { font-size: 14px; }
  .wrap { padding: 0 18px; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
}

/* ───── 和谁做朋友 ───── */
.friend-quote {
  max-width: 780px;
  margin: 0 auto 42px;
  background: var(--card-2);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 26px 30px;
}
.friend-quote p {
  font-size: 19.5px;
  line-height: 1.7;
  color: var(--text);
}
.friend-quote span {
  display: block;
  margin-top: 12px;
  font-size: 13.5px;
  color: var(--dim);
}
.friend-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}
.friend-card {
  background: var(--card-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px 22px;
  transition: transform .2s ease, border-color .2s ease, background .2s ease;
}
.friend-card:hover {
  transform: translateY(-5px);
  border-color: rgba(255, 215, 0, .34);
  background: rgba(255, 215, 0, .04);
}
.friend-card h3 { font-size: 17px; margin-bottom: 4px; }
.friend-count {
  display: block;
  font-size: 12.5px;
  color: var(--accent);
  margin-bottom: 14px;
}
.friend-names { display: flex; flex-wrap: wrap; gap: 8px; }
.friend-names span {
  font-size: 13px;
  color: var(--sub);
  background: rgba(255, 255, 255, .06);
  border-radius: 999px;
  padding: 4px 12px;
}
.friend-tip {
  margin-top: 30px;
  text-align: center;
  font-size: 15px;
  color: var(--sub);
}
.friend-tip strong { color: var(--accent); }

@media (max-width: 900px) {
  .friend-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 620px) {
  .friend-grid { grid-template-columns: 1fr; }
  .friend-quote { padding: 22px 20px; }
  .friend-quote p { font-size: 17px; }
}