/* 公开介绍页：暖白 + 墨绿，移动端优先 */
:root {
  --bg: #f4f2ea;
  --card: #fffdf8;
  --card-2: #fbf9f2;
  --ink: #263238;
  --muted: #6b7780;
  --line: #ddd8cb;
  --green: #1f6f5c;
  --green-deep: #155445;
  --green-soft: #e4efe9;
  --amber: #b7791f;
  --amber-soft: #f6ecd9;
  --shadow: 0 18px 45px rgba(32, 44, 39, 0.08);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121816;
    --card: #1b2421;
    --card-2: #202b27;
    --ink: #e8ecea;
    --muted: #98a6a0;
    --line: #2c3934;
    --green: #79c9ab;
    --green-deep: #a5dfc8;
    --green-soft: #223430;
    --amber: #e0b36a;
    --amber-soft: #332b1f;
    --shadow: 0 18px 45px rgba(0, 0, 0, 0.35);
  }
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 24px;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--bg);
  font: 15px/1.7 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

.glow {
  position: fixed;
  z-index: 0;
  width: 620px;
  height: 620px;
  border-radius: 50%;
  filter: blur(100px);
  opacity: 0.5;
  pointer-events: none;
}
.glow-a { top: -260px; left: -180px; background: var(--green-soft); }
.glow-b { top: 180px; right: -300px; background: var(--amber-soft); opacity: 0.45; }

.page {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 1040px;
  margin: 0 auto;
  padding: 24px 22px 40px;
}

/* ------------------------------------------------------------- 顶部 */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding-bottom: 26px;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.brand-mark {
  width: 42px;
  height: 42px;
  flex: 0 0 42px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: linear-gradient(145deg, var(--green), var(--green-deep));
  color: #fff;
  font-size: 20px;
  font-weight: 700;
  box-shadow: 0 8px 20px rgba(31, 111, 92, 0.25);
}

.brand h1 {
  margin: 0;
  font-size: 16px;
  letter-spacing: 0.01em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.brand p {
  margin: 1px 0 0;
  font-size: 12px;
  color: var(--muted);
}

.top-nav {
  display: flex;
  align-items: center;
  gap: 18px;
  flex: 0 0 auto;
}

.top-nav a {
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
  transition: color .15s;
}
.top-nav a:hover { color: var(--ink); }

.chip {
  display: inline-flex;
  align-items: center;
  padding: 8px 15px;
  border-radius: 999px;
  border: 1px solid var(--line);
  font-size: 13px;
  text-decoration: none;
  background: var(--card);
  transition: border-color .15s, transform .15s, filter .15s;
}
.chip:hover { border-color: var(--green); transform: translateY(-1px); }
.chip.primary {
  background: var(--green);
  border-color: transparent;
  color: #fff;
  font-weight: 600;
}
.chip.primary:hover { filter: brightness(1.06); }

/* ------------------------------------------------------------- Hero */
.hero {
  padding: 64px 0 44px;
  max-width: 720px;
}

.eyebrow {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--green);
}

.hero h2 {
  margin: 0 0 18px;
  font-size: clamp(40px, 7vw, 64px);
  line-height: 1.12;
  letter-spacing: -0.02em;
}

.hero .sub {
  margin: 0;
  max-width: 560px;
  font-size: 16px;
  color: var(--muted);
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 30px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 16px;
  border-radius: 11px;
  border: 1px solid var(--line);
  background: var(--card-2);
  color: var(--ink);
  font-size: 13px;
  font-weight: 500;
  text-decoration: none;
  transition: border-color .15s, transform .15s, filter .15s;
}
.btn:hover { border-color: var(--green); transform: translateY(-1px); }

.btn.primary {
  background: var(--green);
  border-color: transparent;
  color: #fff;
}
.btn.primary:hover { filter: brightness(1.06); }

.btn.lg {
  padding: 13px 24px;
  font-size: 15px;
  border-radius: 12px;
}

.login-hint {
  margin: 14px 0 0;
  font-size: 12px;
  color: var(--muted);
}

/* ------------------------------------------------------------- 数字条 */
.stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--card);
  box-shadow: var(--shadow);
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 4px 10px;
}
.stat + .stat { border-left: 1px solid var(--line); }

.stat b {
  font-size: 27px;
  line-height: 1.15;
  letter-spacing: -0.01em;
}

.stat span { font-size: 12px; color: var(--muted); }

/* ------------------------------------------------------------- 通用 section */
.section { margin-top: 76px; }

.section-head {
  max-width: 620px;
  margin-bottom: 24px;
}

.section-head h2 {
  margin: 0 0 8px;
  font-size: clamp(24px, 3.4vw, 32px);
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.section-head p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

/* ------------------------------------------------------------- 题库卡片 */
.banks {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.bank-card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--card);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.bank-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 4px;
  background: var(--green);
}
.bank-lecture::before { background: var(--amber); }

.bank-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.bank-head h3 { margin: 0 0 4px; font-size: 21px; }

.bank-desc { margin: 0; font-size: 12px; color: var(--muted); }

.tag {
  flex: 0 0 auto;
  padding: 5px 11px;
  border-radius: 999px;
  background: var(--green-soft);
  color: var(--green);
  font-size: 12px;
  font-weight: 600;
  white-space: nowrap;
}
.bank-lecture .tag { background: var(--amber-soft); color: var(--amber); }

.bank-list {
  margin: 0 0 22px;
  padding: 0;
  list-style: none;
  color: var(--muted);
  font-size: 13px;
}
.bank-list li {
  position: relative;
  padding-left: 18px;
  margin: 7px 0;
}
.bank-list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 0.72em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--green);
  opacity: .55;
}
.bank-lecture .bank-list li::before { background: var(--amber); }

.bank-card .btn { margin-top: auto; align-self: flex-start; }

/* ------------------------------------------------------------- 功能 */
.features {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.feature {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--card);
}

.feature-icon {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  margin-bottom: 12px;
  border-radius: 10px;
  background: var(--green-soft);
  color: var(--green);
  font-size: 16px;
  font-weight: 700;
}

.feature h3 { margin: 0 0 6px; font-size: 16px; }
.feature p { margin: 0; font-size: 13px; color: var(--muted); }

/* ------------------------------------------------------------- 步骤 */
.steps ol {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.steps li {
  display: flex;
  gap: 14px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--card);
}

.steps li > span {
  flex: 0 0 30px;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--green);
  color: #fff;
  font-size: 13px;
  font-weight: 700;
}

.steps b { display: block; margin-bottom: 3px; font-size: 15px; }
.steps p { margin: 0; font-size: 12px; color: var(--muted); }

/* ------------------------------------------------------------- 底部 CTA */
.cta-band {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-top: 76px;
  padding: 30px;
  border-radius: 20px;
  background: linear-gradient(135deg, var(--green), var(--green-deep));
  color: #fff;
  box-shadow: 0 20px 45px rgba(27, 92, 76, 0.25);
}

.cta-band h2 { margin: 0 0 6px; font-size: 24px; }
.cta-band p { margin: 0; font-size: 13px; opacity: .85; }

.cta-band .btn.primary {
  background: #fff;
  color: var(--green-deep);
  flex: 0 0 auto;
}
.cta-band .btn.primary:hover { filter: none; opacity: .92; }

/* ------------------------------------------------------------- 页脚 */
.footer {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 56px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  color: var(--muted);
}
.footer .dot { opacity: .6; }

/* ------------------------------------------------------------- 响应式 */
@media (max-width: 760px) {
  .page { padding: 20px 16px 32px; }
  .top-nav a:not(.chip) { display: none; }
  .brand h1 { font-size: 14px; white-space: normal; }
  .hero { padding: 44px 0 32px; }
  .hero .sub { font-size: 15px; }
  .stats { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px 8px; padding: 16px; }
  .stat:nth-child(3) { border-left: 0; }
  .stat b { font-size: 24px; }
  .section { margin-top: 56px; }
  .banks, .features, .steps ol { grid-template-columns: 1fr; }
  .cta-band { flex-direction: column; align-items: flex-start; margin-top: 56px; padding: 24px; }
  .footer { margin-top: 40px; }
}

@media (max-width: 380px) {
  .brand-mark { width: 36px; height: 36px; flex-basis: 36px; font-size: 17px; }
  .btn.lg { width: 100%; }
  .cta-row { flex-direction: column; }
}