/* 谱云 AI 课堂 · 站点设计系统
   面向中小学老师：明亮、可信、信息密度适中。深色只用于「生成过程回放」这类
   用来「看机器在干活」的区块，正文一律浅底深字。 */

:root {
  --bg: #f5f8ff;
  --bg-soft: #eef3ff;
  --panel: #ffffff;
  --panel2: #f8faff;
  --line: #e2e8fa;
  --line-soft: #eef2fd;

  --ink: #131a33;
  --ink-soft: #4c5878;
  --ink-dim: #8590b3;
  --ink-invert: #eaf0ff;

  --brand: #4a6cf7;
  --brand-deep: #3550d8;
  --brand2: #12b5c9;
  --sun: #ffb020;
  --grass: #22c58b;
  --berry: #ff6b8b;
  --violet: #8b5cf6;

  --ok: #12a05f;
  --warn: #c47b00;
  --bad: #d93b40;

  --nav-h: 66px;
  --radius: 18px;
  --radius-sm: 12px;
  --radius-lg: 26px;

  --shadow-xs: 0 2px 8px rgba(35, 58, 130, .05);
  --shadow: 0 10px 30px rgba(35, 58, 130, .09);
  --shadow-lg: 0 22px 56px rgba(35, 58, 130, .14);
  --shadow-brand: 0 14px 30px rgba(74, 108, 247, .28);

  --font: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui,
          -apple-system, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, "Courier New", monospace;

  --wrap: 1200px;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
  background:
    radial-gradient(1100px 520px at 6% -12%, rgba(74, 108, 247, .13), transparent 62%),
    radial-gradient(900px 460px at 98% -2%, rgba(18, 181, 201, .12), transparent 58%),
    radial-gradient(760px 420px at 50% 106%, rgba(255, 176, 32, .10), transparent 62%),
    var(--bg);
  background-attachment: fixed;
}

a { color: var(--brand-deep); text-decoration: none; }
a:hover { color: var(--brand); }
img { max-width: 100%; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 22px; }
.wrap-narrow { max-width: 880px; margin: 0 auto; padding: 0 22px; }

/* ------------------------------------------------------------------ 导航 */
.site-nav {
  position: sticky; top: 0; z-index: 60;
  backdrop-filter: saturate(1.5) blur(14px);
  background: rgba(255, 255, 255, .82);
  border-bottom: 1px solid var(--line);
}
.site-nav .inner {
  max-width: var(--wrap); margin: 0 auto; padding: 0 22px;
  height: var(--nav-h); display: flex; align-items: center; gap: 26px;
}
.brand { display: flex; align-items: center; gap: 11px; color: var(--ink); font-weight: 800; }
.brand:hover { color: var(--ink); }
.brand .mark {
  width: 38px; height: 38px; border-radius: 12px; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--brand), var(--brand2));
  box-shadow: 0 8px 18px rgba(74, 108, 247, .3); position: relative; flex: none;
}
.brand .mark::after {
  content: ""; position: absolute; right: -3px; top: -3px; width: 12px; height: 12px;
  border-radius: 50%; background: var(--sun); box-shadow: 0 0 0 2.5px #fff;
}
.brand .mark svg { width: 21px; height: 21px; fill: #fff; }
.brand .txt b { display: block; font-size: 16.5px; letter-spacing: .2px; line-height: 1.25; }
.brand .txt span { display: block; font-size: 11px; color: var(--ink-dim); font-weight: 500; letter-spacing: .5px; }

.nav-links { display: flex; align-items: center; gap: 4px; margin-left: 6px; }
.nav-links a {
  color: var(--ink-soft); font-size: 14px; font-weight: 600;
  padding: 8px 13px; border-radius: 10px; transition: all .15s;
}
.nav-links a:hover { color: var(--brand); background: rgba(74, 108, 247, .07); }
.nav-links a.on { color: var(--brand); background: rgba(74, 108, 247, .1); }

.nav-right { margin-left: auto; display: flex; align-items: center; gap: 10px; }
.nav-user {
  display: flex; align-items: center; gap: 9px; padding: 5px 12px 5px 5px;
  border: 1px solid var(--line); border-radius: 999px; background: #fff;
  box-shadow: var(--shadow-xs); cursor: pointer; color: var(--ink); font-family: inherit;
}
.nav-user:hover { border-color: var(--brand); }
.nav-user .avatar {
  width: 28px; height: 28px; border-radius: 50%; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--brand), var(--brand2));
  color: #fff; font-size: 12.5px; font-weight: 700; flex: none;
}
.nav-user .nm { font-size: 13px; font-weight: 650; max-width: 96px;
                overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.nav-toggle {
  display: none; margin-left: auto; width: 40px; height: 40px; border-radius: 11px;
  border: 1px solid var(--line); background: #fff; cursor: pointer;
  align-items: center; justify-content: center;
}
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after {
  content: ""; display: block; width: 17px; height: 2px; background: var(--ink-soft);
  border-radius: 2px; position: relative;
}
.nav-toggle span::before { position: absolute; top: -5.5px; }
.nav-toggle span::after { position: absolute; top: 5.5px; }

@media (max-width: 900px) {
  .nav-links {
    display: none; position: absolute; left: 0; right: 0; top: var(--nav-h);
    flex-direction: column; align-items: stretch; gap: 2px; padding: 10px 18px 16px;
    background: #fff; border-bottom: 1px solid var(--line); box-shadow: var(--shadow);
  }
  .nav-links.open { display: flex; }
  .nav-toggle { display: flex; margin-left: auto; }
  .nav-right .nm { display: none; }
}

/* ------------------------------------------------------------------ 按钮 */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  padding: 12px 22px; border: 0; border-radius: 13px; cursor: pointer;
  font-family: inherit; font-size: 14.5px; font-weight: 700; color: #fff;
  background: linear-gradient(135deg, var(--brand), var(--brand2));
  box-shadow: var(--shadow-brand); transition: transform .16s, filter .16s, box-shadow .16s;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-1.5px); filter: brightness(1.05); color: #fff; }
.btn:active { transform: translateY(0); }
.btn:disabled { opacity: .55; cursor: not-allowed; box-shadow: none; transform: none; }
.btn.sm { padding: 9px 16px; font-size: 13px; border-radius: 11px; }
.btn.lg { padding: 15px 30px; font-size: 16px; border-radius: 15px; }
.btn.ghost {
  background: #fff; color: var(--ink-soft); border: 1px solid var(--line);
  box-shadow: var(--shadow-xs); font-weight: 650;
}
.btn.ghost:hover { color: var(--brand); border-color: var(--brand); }
.btn.soft {
  background: rgba(74, 108, 247, .1); color: var(--brand-deep); box-shadow: none;
}
.btn.soft:hover { background: rgba(74, 108, 247, .16); }
.btn.danger { background: #fff; color: var(--bad); border: 1px solid rgba(217, 59, 64, .3);
              box-shadow: none; }

/* ------------------------------------------------------------------ 版面 */
.section { padding: 74px 0; }
.section.tight { padding: 48px 0; }
.section-head { max-width: 760px; margin: 0 auto 40px; text-align: center; }
.section-head.left { margin-left: 0; text-align: left; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 7px; font-size: 12.5px; font-weight: 700;
  letter-spacing: 1.2px; color: var(--brand); text-transform: uppercase;
  background: rgba(74, 108, 247, .1); border-radius: 999px; padding: 5px 13px; margin-bottom: 14px;
}
.section-head h2 { font-size: 32px; line-height: 1.28; margin: 0 0 12px; letter-spacing: -.4px; }
.section-head p { color: var(--ink-soft); font-size: 16px; margin: 0; }
.section-head h2 .hl {
  background: linear-gradient(180deg, transparent 62%, rgba(255, 176, 32, .38) 62%);
  padding: 0 2px;
}

.grid { display: grid; gap: 20px; }
.g2 { grid-template-columns: repeat(2, 1fr); }
.g3 { grid-template-columns: repeat(3, 1fr); }
.g4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 980px) { .g3, .g4 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 700px) { .g2, .g3, .g4 { grid-template-columns: 1fr; } }

.card {
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 24px;
}
.card.flat { box-shadow: var(--shadow-xs); }
.card.pad-lg { padding: 30px; }
.card h3 { font-size: 17px; margin: 0 0 8px; font-weight: 750; }
.card p { color: var(--ink-soft); font-size: 14px; margin: 0; }

/* ------------------------------------------------------------------ Hero */
.hero { padding: 64px 0 56px; position: relative; overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: 1.03fr .97fr; gap: 48px; align-items: center; }
@media (max-width: 1000px) { .hero-grid { grid-template-columns: 1fr; gap: 34px; } }
.hero h1 {
  font-size: 46px; line-height: 1.2; margin: 16px 0 18px; letter-spacing: -1.1px;
  font-weight: 800;
}
.hero h1 .grad {
  background: linear-gradient(120deg, var(--brand), var(--brand2) 62%, var(--violet));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero .lede { font-size: 17px; color: var(--ink-soft); margin: 0 0 26px; max-width: 560px; }
.hero .cta { display: flex; gap: 12px; flex-wrap: wrap; align-items: center; }
.hero .cta .note { font-size: 12.5px; color: var(--ink-dim); }
.hero-stats { display: flex; gap: 30px; margin-top: 34px; flex-wrap: wrap; }
.hero-stats div b { display: block; font-size: 24px; font-weight: 800; letter-spacing: -.5px; }
.hero-stats div span { font-size: 12.5px; color: var(--ink-dim); }

/* 输入一句话 → 课件的示意卡 */
.pitch-card {
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg); padding: 26px; position: relative;
}
.pitch-card::before {
  content: ""; position: absolute; inset: -1px; border-radius: inherit; padding: 1px;
  background: linear-gradient(135deg, rgba(74, 108, 247, .5), rgba(18, 181, 201, .35), transparent 70%);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor; mask-composite: exclude; pointer-events: none;
}
.pitch-line {
  display: flex; align-items: center; gap: 10px; background: var(--panel2);
  border: 1px solid var(--line); border-radius: 13px; padding: 13px 15px; font-size: 14.5px;
}
.pitch-line .cursor {
  width: 2px; height: 19px; background: var(--brand); display: inline-block;
  animation: blink 1.05s steps(1) infinite;
}
@keyframes blink { 50% { opacity: 0; } }
.pitch-arrow { text-align: center; color: var(--ink-dim); padding: 12px 0 10px; font-size: 12.5px; }
.pitch-arrow::before { content: "↓"; display: block; font-size: 17px; color: var(--brand); }
.pitch-out { display: grid; grid-template-columns: repeat(3, 1fr); gap: 9px; }
.pitch-out div {
  border: 1px solid var(--line); border-radius: 12px; background: var(--panel2);
  padding: 11px; text-align: center;
}
.pitch-out b { display: block; font-size: 13px; font-weight: 700; }
.pitch-out span { font-size: 11px; color: var(--ink-dim); }

/* ------------------------------------------------------------------ 标签 */
.pill {
  display: inline-flex; align-items: center; gap: 6px; font-size: 12px; font-weight: 650;
  padding: 4px 11px; border-radius: 999px; border: 1px solid var(--line);
  color: var(--ink-soft); background: #fff;
}
.pill.brand { color: var(--brand-deep); border-color: rgba(74, 108, 247, .3);
              background: rgba(74, 108, 247, .09); }
.pill.grass { color: #0b7a48; border-color: rgba(18, 160, 95, .3);
              background: rgba(18, 160, 95, .09); }
.pill.sun { color: #8a5a00; border-color: rgba(255, 176, 32, .38);
            background: rgba(255, 176, 32, .14); }
.pill.violet { color: #5b32c9; border-color: rgba(139, 92, 246, .3);
               background: rgba(139, 92, 246, .1); }

/* ------------------------------------------------------------------ 表单 */
label { display: block; font-size: 13px; color: var(--ink-soft); margin: 16px 0 7px; font-weight: 650; }
label .opt { color: var(--ink-dim); font-weight: 400; }
input[type=text], input[type=password], input[type=email], textarea, select {
  width: 100%; padding: 12px 14px; border-radius: var(--radius-sm); color: var(--ink);
  font-size: 14.5px; background: var(--panel2); border: 1px solid var(--line); outline: none;
  font-family: inherit; transition: border-color .16s, box-shadow .16s, background .16s;
}
input:focus, textarea:focus, select:focus {
  border-color: var(--brand); background: #fff; box-shadow: 0 0 0 3px rgba(74, 108, 247, .14);
}
textarea { resize: vertical; min-height: 72px; line-height: 1.65; }
select {
  appearance: none; cursor: pointer; padding-right: 36px;
  background-image: linear-gradient(45deg, transparent 50%, var(--ink-dim) 50%),
                    linear-gradient(135deg, var(--ink-dim) 50%, transparent 50%);
  background-position: calc(100% - 19px) 50%, calc(100% - 14px) 50%;
  background-size: 5px 5px, 5px 5px; background-repeat: no-repeat;
}
.form-note { font-size: 12.5px; color: var(--ink-dim); margin-top: 9px; }
.field-err { font-size: 12.5px; color: var(--bad); margin-top: 7px; min-height: 18px; }

/* ------------------------------------------------------------------ 步骤 / 流程 */
.flow { display: grid; grid-template-columns: repeat(5, 1fr); gap: 14px; counter-reset: s; }
@media (max-width: 1000px) { .flow { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 620px) { .flow { grid-template-columns: 1fr; } }
.flow-card {
  position: relative; background: var(--panel); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 20px 18px; box-shadow: var(--shadow-xs);
  transition: transform .18s, box-shadow .18s, border-color .18s;
}
.flow-card:hover { transform: translateY(-3px); box-shadow: var(--shadow);
                   border-color: rgba(74, 108, 247, .34); }
.flow-card .no {
  counter-increment: s; width: 30px; height: 30px; border-radius: 10px; display: grid;
  place-items: center; font-size: 13px; font-weight: 800; color: #fff; margin-bottom: 12px;
  background: linear-gradient(135deg, var(--brand), var(--brand2));
}
.flow-card .no::before { content: counter(s); }
.flow-card h4 { font-size: 15px; margin: 0 0 7px; font-weight: 750; }
.flow-card p { font-size: 13px; color: var(--ink-soft); margin: 0; }
.flow-card .kv { margin-top: 11px; display: flex; flex-wrap: wrap; gap: 5px; }
.flow-card .kv span {
  font-size: 11px; color: var(--ink-dim); background: var(--panel2);
  border: 1px solid var(--line); border-radius: 6px; padding: 2px 7px;
}

/* 纵向详解（介绍页） */
.deep { display: grid; grid-template-columns: 74px 1fr; gap: 22px; }
@media (max-width: 760px) { .deep { grid-template-columns: 1fr; gap: 12px; } }
.deep-item { display: contents; }
.deep .rail { display: flex; flex-direction: column; align-items: center; }
.deep .rail .n {
  width: 46px; height: 46px; border-radius: 15px; display: grid; place-items: center;
  font-size: 17px; font-weight: 800; color: #fff; flex: none;
  background: linear-gradient(135deg, var(--brand), var(--brand2));
  box-shadow: 0 10px 22px rgba(74, 108, 247, .26);
}
.deep .rail .dash { flex: 1; width: 2px; background: linear-gradient(var(--line), transparent);
                    margin: 10px 0; min-height: 30px; }
.deep .body { padding-bottom: 34px; }
.deep .body h3 { font-size: 20px; margin: 6px 0 10px; font-weight: 780; letter-spacing: -.2px; }
.deep .body p { color: var(--ink-soft); margin: 0 0 14px; }
.deep .body p.lead { font-size: 15.5px; }
.deep-photo {
  background: linear-gradient(180deg, #0f1730, #16203f); border-radius: var(--radius);
  padding: 18px 20px; border: 1px solid #23306a; overflow: hidden;
}
.deep-photo .t {
  font-size: 11.5px; color: #7d8ec7; letter-spacing: 1.1px; text-transform: uppercase;
  margin-bottom: 10px; font-weight: 700;
}
.deep-photo pre {
  margin: 0; font-family: var(--mono); font-size: 12px; line-height: 1.85;
  color: #b9c8f5; white-space: pre-wrap; word-break: break-word; max-height: 300px; overflow: auto;
}
.deep-photo pre .ok { color: #5fe0a8; }
.deep-photo pre .k { color: #8fb4ff; }
.deep-photo pre .num { color: var(--sun); }
.deep-photo pre .dim { color: #6b7aa8; }

.callout {
  border-left: 3px solid var(--brand); background: rgba(74, 108, 247, .06);
  border-radius: 0 12px 12px 0; padding: 13px 16px; font-size: 13.5px; color: var(--ink-soft);
}
.callout.grass { border-color: var(--grass); background: rgba(34, 197, 139, .07); }
.callout.sun { border-color: var(--sun); background: rgba(255, 176, 32, .1); }

/* ------------------------------------------------------------------ 表格 */
.tbl { width: 100%; border-collapse: collapse; font-size: 14px; }
.tbl th, .tbl td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--line); }
.tbl th { font-size: 12.5px; color: var(--ink-dim); font-weight: 700;
          text-transform: uppercase; letter-spacing: .6px; }
.tbl tbody tr:hover { background: var(--panel2); }
.tbl td.num { font-variant-numeric: tabular-nums; }

/* ------------------------------------------------------------------ 定价 */
.price-card {
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px; box-shadow: var(--shadow); display: flex; flex-direction: column;
  position: relative;
}
.price-card.hot { border-color: rgba(74, 108, 247, .45); box-shadow: var(--shadow-lg); }
.price-card.hot::before {
  content: "最受欢迎"; position: absolute; top: -12px; left: 50%; transform: translateX(-50%);
  background: linear-gradient(135deg, var(--brand), var(--brand2)); color: #fff;
  font-size: 12px; font-weight: 700; padding: 4px 14px; border-radius: 999px;
  box-shadow: var(--shadow-brand); white-space: nowrap;
}
.price-card h3 { font-size: 17px; margin: 0 0 4px; }
.price-card .for { font-size: 13px; color: var(--ink-dim); margin-bottom: 18px; }
.price-card .amt { font-size: 36px; font-weight: 800; letter-spacing: -1px; line-height: 1.1; }
.price-card .amt small { font-size: 14px; font-weight: 600; color: var(--ink-dim); letter-spacing: 0; }
.price-card ul { list-style: none; margin: 20px 0 0; padding: 0; flex: 1; }
.price-card li { font-size: 13.5px; color: var(--ink-soft); padding: 7px 0 7px 24px; position: relative; }
.price-card li::before {
  content: "✓"; position: absolute; left: 0; top: 7px; color: var(--grass); font-weight: 800;
}
.price-card li.off { color: var(--ink-dim); }
.price-card li.off::before { content: "—"; color: var(--ink-dim); }
.price-card .btn { margin-top: 22px; width: 100%; }

/* ------------------------------------------------------------------ 页脚 */
.site-foot {
  border-top: 1px solid var(--line); background: rgba(255, 255, 255, .72);
  margin-top: 40px; padding: 44px 0 30px;
}
.foot-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: 30px; }
@media (max-width: 860px) { .foot-grid { grid-template-columns: 1fr 1fr; } }
.site-foot h5 { font-size: 13px; margin: 0 0 12px; color: var(--ink); font-weight: 750; }
.site-foot a, .site-foot p { display: block; font-size: 13px; color: var(--ink-soft); margin: 0 0 9px; }
.site-foot .copy {
  border-top: 1px solid var(--line-soft); margin-top: 30px; padding-top: 20px;
  font-size: 12.5px; color: var(--ink-dim); display: flex; gap: 14px; flex-wrap: wrap;
  align-items: center; justify-content: space-between;
}

/* ------------------------------------------------------------------ 提示条 */
.toast {
  position: fixed; left: 50%; bottom: 34px; transform: translate(-50%, 20px);
  background: #131a33; color: #fff; border-radius: 12px; padding: 12px 20px;
  font-size: 13.5px; box-shadow: var(--shadow-lg); opacity: 0; pointer-events: none;
  transition: opacity .2s, transform .2s; z-index: 200; max-width: 90vw;
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }
.toast.bad { background: #8c1f23; }
.toast.ok { background: #0d6b40; }

.banner-warn {
  border: 1px solid rgba(196, 123, 0, .32); background: rgba(255, 176, 32, .13);
  border-radius: 12px; padding: 12px 15px; font-size: 13px; color: #7d5200;
}
.banner-warn b { color: #6b4600; }

/* ------------------------------------------------------------------ 通用小件 */
.muted { color: var(--ink-dim); }
.center { text-align: center; }
.stack { display: flex; flex-direction: column; gap: 14px; }
.row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.spacer { flex: 1; }
.mono { font-family: var(--mono); }
.hr { height: 1px; background: var(--line); border: 0; margin: 30px 0; }
.empty { color: var(--ink-dim); font-size: 13.5px; text-align: center; padding: 30px 0; }
code {
  background: var(--panel2); border: 1px solid var(--line); border-radius: 6px;
  padding: 1.5px 6px; font-size: 12.8px; font-family: var(--mono);
}
.skeleton {
  background: linear-gradient(90deg, var(--line-soft) 25%, var(--bg-soft) 37%, var(--line-soft) 63%);
  background-size: 400% 100%; animation: shimmer 1.3s linear infinite; border-radius: 10px;
}
@keyframes shimmer { 0% { background-position: 100% 0; } 100% { background-position: 0 0; } }

.dot { width: 8px; height: 8px; border-radius: 50%; background: var(--ink-dim);
       display: inline-block; margin-right: 7px; vertical-align: 1px; }
.dot.ok { background: var(--ok); box-shadow: 0 0 0 3px rgba(18, 160, 95, .16); }
.dot.bad { background: var(--bad); box-shadow: 0 0 0 3px rgba(217, 59, 64, .16); }

.health-pill {
  display: inline-flex; align-items: center; font-size: 12.5px; color: var(--ink-soft);
  border: 1px solid var(--line); border-radius: 999px; padding: 6px 14px;
  background: rgba(255, 255, 255, .8); box-shadow: var(--shadow-xs);
}

/* 锚点小节（介绍页用） */
.anchor-block { scroll-margin-top: 90px; }