/* 啟研 · 智能体论文写作 —— 全站样式
   版式：仿产品官网，一个班级占一整块，黑白交替；正文用系统中文字体 */

:root {
  --black: #07080b;
  --night: #0f1117;
  --night-2: #171a22;
  --paper: #ffffff;
  --mist: #f3f4f6;
  --text: #16181d;
  --text-2: #3c4049;
  --muted: #6d717c;
  --line: #e2e4e8;
  --on-dark: #f5f6f8;
  --on-dark-2: #a7abb5;
  --line-dark: rgba(255, 255, 255, .12);
  --gold: #f4b740;
  --gold-ink: #8f5d00;
  --ember: #ff7a4d;
  --grad: linear-gradient(92deg, #ffe08a 0%, #f4b740 38%, #ff8a4c 72%, #ff6b6b 100%);
  --ok: #2fb47c;
  --radius: 22px;
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Source Han Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --gutter: 22px;
}

*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; scroll-padding-top: 64px; -webkit-text-size-adjust: 100%; }
body {
  margin: 0; font-family: var(--font); font-size: 17px; line-height: 1.6;
  color: var(--text); background: var(--paper); overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}
body::before {
  content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px);
  z-index: 60; background: var(--black);
}
h1, h2, h3, h4 { margin: 0; line-height: 1.15; font-weight: 700; letter-spacing: -.01em; text-wrap: balance; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }
:focus-visible { outline: 3px solid var(--gold); outline-offset: 3px; border-radius: 6px; }

.wrap {
  width: 100%; max-width: 1180px; margin: 0 auto;
  padding-left: max(var(--gutter), env(safe-area-inset-left, 0px));
  padding-right: max(var(--gutter), env(safe-area-inset-right, 0px));
}
.wrap.narrow { max-width: 860px; }
.nowrap { white-space: nowrap; }
.nb { display: inline-block; }
.grad-text { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  min-height: 44px; padding: 0 22px; border-radius: 999px; border: 1.5px solid transparent;
  font-size: 16px; font-weight: 600; line-height: 1; white-space: nowrap; cursor: pointer;
  transition: transform .2s, background .2s, color .2s, border-color .2s, box-shadow .2s;
}
.btn:hover { transform: translateY(-1px); }
.btn-gold { background: var(--gold); color: #1a1205; }
.btn-gold:hover { box-shadow: 0 6px 24px rgba(244, 183, 64, .45); }
.btn-dark { background: var(--text); color: #fff; }
.btn-light { background: #fff; color: var(--text); }
.btn-outline { border-color: currentColor; background: transparent; }
.on-dark .btn-outline { color: var(--on-dark); }
.btn-link { padding: 0; min-height: 0; border: 0; background: none; color: var(--gold-ink); font-weight: 600; }
.on-dark .btn-link { color: var(--gold); }
.btn-link::after { content: "›"; font-size: 1.25em; line-height: 0; margin-left: 2px; }
.btn[disabled] { opacity: .55; cursor: not-allowed; transform: none; }

/* ---------- 页眉 ---------- */
.site-header {
  position: sticky; top: env(safe-area-inset-top, 0px); z-index: 50;
  background: rgba(7, 8, 11, .78); color: var(--on-dark);
  backdrop-filter: saturate(1.6) blur(18px); -webkit-backdrop-filter: saturate(1.6) blur(18px);
  border-bottom: 1px solid var(--line-dark);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 56px; }
.brand { display: flex; align-items: center; gap: 9px; font-weight: 700; letter-spacing: .06em; }
.brand-mark {
  display: inline-grid; place-items: center; width: 30px; height: 30px; border-radius: 9px;
  background: var(--grad); color: #1a1205; font-size: 17px; font-weight: 800; letter-spacing: 0;
}
.brand-en { font-size: 12px; font-weight: 500; color: var(--on-dark-2); letter-spacing: .04em; margin-left: 2px; }
.site-nav { display: flex; align-items: center; gap: 26px; font-size: 14px; }
.site-nav a { color: var(--on-dark-2); transition: color .2s; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: #fff; }
.site-nav .nav-cta { color: #1a1205; background: var(--gold); padding: 6px 16px; border-radius: 999px; font-weight: 600; }
.site-nav .nav-cta:hover { color: #1a1205; }
.nav-toggle { display: none; width: 40px; height: 40px; border: 0; background: none; padding: 10px; cursor: pointer; }
.nav-toggle span { display: block; height: 2px; background: var(--on-dark); border-radius: 2px; transition: transform .25s, opacity .25s; }
.nav-toggle span + span { margin-top: 6px; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(8px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-8px) rotate(-45deg); }

/* ---------- 首屏 ---------- */
.hero {
  position: relative; isolation: isolate; overflow: hidden;
  background: var(--black); color: var(--on-dark); text-align: center;
  padding-block: 88px 0;
}
.hero::before {
  content: ""; position: absolute; z-index: -1; left: 50%; top: 52%;
  width: 1100px; height: 700px; transform: translateX(-50%);
  background:
    radial-gradient(closest-side, rgba(244, 183, 64, .30), transparent 70%),
    radial-gradient(closest-side at 70% 60%, rgba(255, 107, 107, .18), transparent 70%);
  filter: blur(20px);
  animation: breathe 9s ease-in-out infinite;
}
.hero-kicker { font-size: 15px; color: var(--on-dark-2); letter-spacing: .12em; }
.hero h1 { margin-top: 16px; font-size: clamp(40px, 7.2vw, 84px); letter-spacing: -.02em; line-height: 1.08; }
.hero-sub { text-wrap: balance; margin: 20px auto 0; max-width: 30em; font-size: clamp(18px, 2.2vw, 24px); color: var(--on-dark-2); }
.hero-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 14px; margin-top: 32px; }

.stack { position: relative; height: 380px; margin: 56px auto 0; max-width: 980px; }
.stack-card {
  position: absolute; left: 50%; bottom: -36px; width: min(460px, 64%); height: 300px;
  border-radius: 24px; border: 1px solid var(--line-dark); text-align: left;
  background: linear-gradient(165deg, #20242e, #12141a 70%);
  box-shadow: 0 30px 80px rgba(0, 0, 0, .6);
  padding: 26px 28px;
}
.sc-level { font-size: 12px; letter-spacing: .16em; color: var(--on-dark-2); }
.sc-name { margin-top: 8px; font-size: 28px; font-weight: 700; color: #fff; }
.sc-tag { margin-top: 6px; font-size: 15px; color: var(--on-dark-2); }
.sc-chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 22px; }
.sc-chips span { font-size: 13px; padding: 4px 10px; border-radius: 999px; border: 1px solid var(--line-dark); color: var(--on-dark); background: rgba(255, 255, 255, .04); }
.sc-1 { transform: translateX(-50%) translateX(-64%) rotate(-5deg) scale(.88); animation: float1 8s ease-in-out infinite; }
.sc-3 { transform: translateX(-50%) translateX(64%) rotate(5deg) scale(.88); text-align: right; animation: float3 8s ease-in-out infinite; }
.sc-3 .sc-chips { justify-content: flex-end; }
.sc-2 {
  transform: translateX(-50%) translateY(-26px); z-index: 2;
  background: linear-gradient(165deg, #3a2a10, #1c1710 55%, #131318);
  border-color: rgba(244, 183, 64, .5);
  box-shadow: 0 30px 90px rgba(0, 0, 0, .6), 0 0 80px rgba(244, 183, 64, .18);
  animation: float2 8s ease-in-out infinite;
}
.sc-2 .sc-name { font-size: 32px; }
.sc-2 .sc-chips span { border-color: rgba(244, 183, 64, .4); }
.sc-badge {
  position: absolute; top: 22px; right: 24px; font-size: 12px; font-weight: 700; color: #1a1205;
  background: var(--gold); padding: 3px 10px; border-radius: 999px;
}

/* ---------- 班级大块 ---------- */
.tile { position: relative; overflow: hidden; isolation: isolate; text-align: center; padding-block: 84px 0; }
.tile + .tile { border-top: 12px solid var(--paper); }
.tile-light { background: var(--mist); color: var(--text); }
.tile-dark { background: var(--black); color: var(--on-dark); }
.tile-eyebrow { font-size: 17px; font-weight: 600; color: var(--gold-ink); }
.tile-dark .tile-eyebrow { color: var(--gold); }
.tile h2 { margin-top: 8px; font-size: clamp(38px, 5.6vw, 60px); letter-spacing: -.015em; }
.tile-tagline { text-wrap: balance; margin-top: 10px; font-size: clamp(19px, 2.4vw, 27px); color: var(--text-2); }
.tile-dark .tile-tagline { color: var(--on-dark-2); }
.tile-meta { margin-top: 12px; font-size: 15px; color: var(--muted); }
.tile-dark .tile-meta { color: var(--on-dark-2); }
.tile-actions { display: flex; flex-wrap: wrap; justify-content: center; align-items: center; gap: 14px 22px; margin-top: 26px; }
.tile-visual { margin: 52px auto 0; max-width: 760px; position: relative; }

/* 初级班：终端 */
.term {
  margin: 0 auto; width: min(640px, 100%); text-align: left; border-radius: 16px 16px 0 0;
  background: #0d0f14; color: #d9dde5; box-shadow: 0 -10px 60px rgba(17, 24, 39, .25);
  font-family: var(--mono); font-size: 14.5px; overflow: hidden;
}
.term-bar { display: flex; gap: 7px; padding: 13px 16px; background: #181b22; }
.term-bar i { width: 11px; height: 11px; border-radius: 50%; background: #3a3f4b; }
.term-bar i:nth-child(1) { background: #ff5f57; } .term-bar i:nth-child(2) { background: #febc2e; } .term-bar i:nth-child(3) { background: #28c840; }
.term-body { padding: 22px 24px 34px; display: grid; gap: 10px; line-height: 1.6; }
.term-body .p { color: #fff; }
.term-body .p::before { content: "› "; color: var(--gold); }
.term-body .o { color: #9aa1ad; padding-left: 16px; }
.term-body .o b { color: var(--ok); font-weight: 600; margin-right: 6px; }
.term-body .cursor { display: inline-block; width: 9px; height: 1.1em; vertical-align: -3px; background: var(--gold); animation: blink 1.1s steps(1) infinite; }

/* 中级班：稿纸与批注 */
.manuscript { position: relative; height: 430px; perspective: 1600px; }
.page {
  position: absolute; left: 50%; bottom: 0; width: min(520px, 86%); height: 400px;
  background: #fbfbf8; border-radius: 10px 10px 0 0; text-align: left;
  box-shadow: 0 -20px 80px rgba(244, 183, 64, .18), 0 0 0 1px rgba(255, 255, 255, .06);
  transform: translateX(-50%) rotateX(14deg); transform-origin: 50% 100%;
  padding: 34px 38px; color: #2a2d33;
}
.page-back { transform: translateX(-50%) translateX(-6%) rotateX(14deg) rotateZ(-5deg); opacity: .35; background: #e9e9e4; }
.page h4 { font-size: 15px; font-weight: 700; color: #1d1f24; letter-spacing: 0; }
.page .ln { display: block; height: 8px; border-radius: 4px; background: #d9dbe0; margin-top: 14px; }
.page .ln.w9 { width: 92%; } .page .ln.w8 { width: 80%; } .page .ln.w6 { width: 60%; } .page .ln.w7 { width: 72%; }
.page .hl-ln {
  background: linear-gradient(90deg, rgba(244, 183, 64, .85), rgba(244, 183, 64, .85)) no-repeat;
  background-size: 100% 100%; animation: sweep 1.6s ease-out .4s both;
}
.note {
  position: absolute; z-index: 3; max-width: 230px; text-align: left; font-size: 14px; line-height: 1.45;
  background: rgba(23, 26, 34, .92); color: var(--on-dark); border: 1px solid rgba(244, 183, 64, .5);
  border-radius: 12px; padding: 10px 14px; box-shadow: 0 14px 40px rgba(0, 0, 0, .45);
  backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px);
}
.note b { display: block; font-size: 12px; color: var(--gold); font-weight: 700; letter-spacing: .06em; margin-bottom: 2px; }
.note-a { left: 2%; top: 60px; animation: float1 7s ease-in-out infinite; }
.note-b { right: 1%; top: 150px; animation: float3 7.5s ease-in-out infinite; }
.note-c { left: 6%; top: 250px; animation: float2 8s ease-in-out infinite; }

/* 高级班：回复信 */
.letter {
  margin: 0 auto; width: min(600px, 100%); text-align: left; background: #fff; color: var(--text);
  border-radius: 18px 18px 0 0; padding: 28px 30px 36px;
  box-shadow: 0 -12px 60px rgba(17, 24, 39, .14);
}
.letter-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; border-bottom: 1px solid var(--line); padding-bottom: 14px; }
.letter-head h4 { font-size: 17px; letter-spacing: 0; }
.status { font-size: 12px; font-weight: 700; color: #1a1205; background: var(--gold); padding: 4px 11px; border-radius: 999px; white-space: nowrap; }
.letter ol { display: grid; gap: 12px; margin-top: 16px; }
.letter li { display: grid; grid-template-columns: 74px 1fr 26px; gap: 12px; align-items: center; font-size: 15px; }
.letter li span:first-child { font-family: var(--mono); font-size: 13px; color: var(--muted); }
.letter li .ck {
  width: 24px; height: 24px; border-radius: 50%; background: var(--ok); color: #fff;
  display: grid; place-items: center; font-size: 13px; font-weight: 700;
  animation: pop .5s ease-out both;
}
.letter li:nth-child(2) .ck { animation-delay: .25s; } .letter li:nth-child(3) .ck { animation-delay: .5s; } .letter li:nth-child(4) .ck { animation-delay: .75s; }
.steps { display: flex; justify-content: center; flex-wrap: wrap; gap: 8px; margin-top: 18px; font-size: 13px; color: var(--muted); }
.steps span { padding: 4px 10px; border: 1px solid var(--line); border-radius: 999px; background: #fff; }
.steps span.on { border-color: var(--gold); color: var(--gold-ink); font-weight: 600; }

/* ---------- 双栏小块 ---------- */
.duo { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; padding: 12px; background: var(--paper); }
.mini { border-radius: 4px; padding-block: 64px 56px; text-align: center; position: relative; overflow: hidden; isolation: isolate; }
.mini h3 { font-size: clamp(30px, 3.8vw, 42px); margin-top: 6px; }
.mini p.mini-sub { margin-top: 10px; font-size: 19px; color: var(--text-2); }
.mini.tile-dark p.mini-sub { color: var(--on-dark-2); }
.mini .tile-actions { margin-top: 22px; }
.mini-art { margin-top: 34px; display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; }
.file-chip {
  display: flex; align-items: center; gap: 10px; padding: 12px 16px; border-radius: 14px; font-size: 14px;
  background: #fff; border: 1px solid var(--line); box-shadow: 0 6px 20px rgba(17, 24, 39, .06);
}
.file-chip i { width: 26px; height: 32px; border-radius: 4px; background: linear-gradient(160deg, #ffe08a, #f4b740); position: relative; }
.file-chip i::after { content: ""; position: absolute; right: 0; top: 0; border: 6px solid transparent; border-top-color: #fff; border-right-color: #fff; }
.org-chip { padding: 10px 16px; border-radius: 999px; border: 1px solid var(--line-dark); font-size: 14px; color: var(--on-dark); background: rgba(255, 255, 255, .05); }

/* ---------- 对比 ---------- */
.section { padding-block: 96px; }
.section-mist { background: var(--mist); }
.section-dark { background: var(--black); color: var(--on-dark); }
.sec-title { text-align: center; font-size: clamp(32px, 4.6vw, 52px); letter-spacing: -.015em; }
.sec-sub { text-align: center; margin-top: 12px; font-size: clamp(17px, 2vw, 21px); color: var(--muted); }
.section-dark .sec-sub { color: var(--on-dark-2); }

.compare { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin-top: 56px; }
.cmp { padding: 0 26px; text-align: center; display: flex; flex-direction: column; align-items: center; min-width: 0; }
.cmp + .cmp { border-left: 1px solid var(--line); }
.cmp-icon {
  width: 72px; height: 72px; border-radius: 20px; display: grid; place-items: center;
  font-size: 28px; font-weight: 800; color: #1a1205; background: var(--grad);
}
.cmp-icon.c1 { background: linear-gradient(160deg, #fff1c4, #f4d27a); }
.cmp-icon.c3 { background: linear-gradient(160deg, #ffb48f, #ff6b6b); color: #fff; }
.cmp h3 { margin-top: 18px; font-size: 26px; }
.cmp .cmp-tag { margin-top: 6px; color: var(--text-2); font-size: 16px; }
.cmp .price { margin-top: 18px; font-size: 18px; font-weight: 700; }
.cmp .price small { display: block; font-size: 13px; font-weight: 400; color: var(--muted); margin-top: 2px; }
.cmp .tile-actions { margin-top: 18px; }
.cmp dl { margin: 28px 0 0; width: 100%; display: grid; gap: 0; }
.cmp dl div { padding: 16px 0; border-top: 1px solid var(--line); }
.cmp dt { font-size: 13px; color: var(--muted); }
.cmp dd { margin: 4px 0 0; font-size: 16px; color: var(--text); }

/* ---------- 实绩 ---------- */
.proof { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 56px; }
.proof div { padding: 30px 28px; border-radius: var(--radius); background: var(--night-2); border: 1px solid var(--line-dark); }
.proof b { display: block; font-size: clamp(46px, 6vw, 68px); line-height: 1; font-weight: 800; letter-spacing: -.02em; font-variant-numeric: tabular-nums; }
.proof b small { font-size: .38em; font-weight: 600; margin-left: 6px; letter-spacing: 0; }
.proof p { margin-top: 12px; color: var(--on-dark-2); font-size: 16px; }
.proof-note { margin-top: 18px; text-align: center; font-size: 13px; color: var(--on-dark-2); }

.teacher-card {
  margin-top: 64px; display: grid; grid-template-columns: auto 1fr; gap: 28px; align-items: center;
  padding: 32px; border-radius: var(--radius); border: 1px solid var(--line-dark);
  background: linear-gradient(120deg, rgba(244, 183, 64, .12), rgba(255, 255, 255, .02) 55%);
}
.avatar { width: 92px; height: 92px; border-radius: 26px; display: grid; place-items: center; font-size: 40px; font-weight: 800; color: #1a1205; background: var(--grad); }
.teacher-card h3 { font-size: 24px; }
.teacher-card .t-title { color: var(--on-dark-2); margin-top: 4px; font-size: 15px; }
.teacher-card ul { margin-top: 14px; display: grid; gap: 6px; font-size: 15.5px; color: var(--on-dark); }
.teacher-card li::before { content: "·"; color: var(--gold); font-weight: 800; margin-right: 8px; }

.promise { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; margin-top: 40px; }
.promise span { padding: 9px 18px; border-radius: 999px; border: 1px solid var(--line-dark); font-size: 15px; color: var(--on-dark); }
.promise span::before { content: "×"; color: var(--gold); font-weight: 800; margin-right: 8px; }

/* ---------- 表单 ---------- */
.lead-wrap { display: grid; grid-template-columns: .9fr 1.1fr; gap: 56px; align-items: start; }
.lead-copy h2 { font-size: clamp(32px, 4.4vw, 48px); letter-spacing: -.015em; }
.lead-copy p { margin-top: 14px; font-size: 18px; color: var(--text-2); }
.lead-points { margin-top: 26px; display: grid; gap: 10px; font-size: 16px; color: var(--text-2); }
.lead-points li::before { content: "✓"; color: var(--ok); font-weight: 800; margin-right: 10px; }
.contact-items { margin-top: 28px; display: grid; gap: 10px; }
.contact-items li { display: flex; gap: 14px; font-size: 16px; }
.contact-items li span:first-child { color: var(--muted); min-width: 3em; }
.form { display: grid; gap: 14px; padding: 30px; border-radius: var(--radius); background: #fff; border: 1px solid var(--line); box-shadow: 0 20px 60px rgba(17, 24, 39, .08); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.field { display: grid; gap: 6px; min-width: 0; }
.field label { font-size: 14px; font-weight: 600; color: var(--text-2); }
.field label .req { color: var(--ember); margin-left: 2px; }
.field input, .field select, .field textarea {
  width: 100%; font: inherit; font-size: 16px; color: var(--text); background: var(--mist);
  border: 1.5px solid transparent; border-radius: 12px; padding: 12px 14px; transition: border-color .2s, background .2s;
}
.field textarea { min-height: 96px; resize: vertical; }
.field input:focus, .field select:focus, .field textarea:focus { outline: none; border-color: var(--gold); background: #fff; }
.hp { position: absolute !important; left: -9999px !important; width: 1px; height: 1px; overflow: hidden; }
.form-foot { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 18px; margin-top: 4px; }
.form-msg { font-size: 14px; color: var(--muted); }
.form-msg.ok { color: #157a52; font-weight: 600; }
.form-msg.err { color: #c2410c; font-weight: 600; }
.form-privacy { font-size: 12.5px; color: var(--muted); }

/* ---------- 悬浮留言 ---------- */
.fab {
  position: fixed; z-index: 70;
  right: calc(20px + env(safe-area-inset-right, 0px)); bottom: calc(20px + env(safe-area-inset-bottom, 0px));
  display: inline-flex; align-items: center; gap: 8px; height: 52px; padding: 0 20px; border-radius: 999px; border: 0;
  background: var(--gold); color: #1a1205; font-weight: 700; font-size: 15px; cursor: pointer;
  box-shadow: 0 10px 30px rgba(244, 183, 64, .45), 0 2px 6px rgba(0, 0, 0, .2);
}
.fab svg { width: 20px; height: 20px; }
.chat {
  position: fixed; z-index: 71;
  right: calc(20px + env(safe-area-inset-right, 0px)); bottom: calc(84px + env(safe-area-inset-bottom, 0px));
  width: min(380px, calc(100vw - 32px)); max-height: calc(100vh - 120px); overflow: auto;
  background: #fff; border-radius: 20px; box-shadow: 0 30px 80px rgba(0, 0, 0, .3); border: 1px solid var(--line);
}
.chat-head { display: flex; justify-content: space-between; align-items: center; padding: 18px 20px 6px; }
.chat-head h3 { font-size: 18px; }
.chat-head button { border: 0; background: var(--mist); width: 32px; height: 32px; border-radius: 50%; cursor: pointer; font-size: 18px; line-height: 1; }
.chat .chat-sub { padding: 0 20px; font-size: 14px; color: var(--muted); }
.chat .form { border: 0; box-shadow: none; padding: 16px 20px 20px; }

/* ---------- 内页 ---------- */
.page-hero { background: var(--black); color: var(--on-dark); text-align: center; padding-block: 72px 64px; position: relative; overflow: hidden; isolation: isolate; }
.page-hero::before { content: ""; position: absolute; z-index: -1; inset: auto 0 -60% 0; height: 120%; background: radial-gradient(closest-side, rgba(244, 183, 64, .22), transparent 70%); }
.page-hero h1 { font-size: clamp(36px, 5.6vw, 60px); letter-spacing: -.015em; }
.page-hero p { margin-top: 12px; font-size: clamp(17px, 2vw, 21px); color: var(--on-dark-2); }

.detail { display: grid; grid-template-columns: 320px 1fr; gap: 48px; padding-block: 72px; border-top: 1px solid var(--line); }
.detail:first-child { border-top: 0; }
.detail-side .tile-eyebrow { font-size: 15px; }
.detail-side h2 { font-size: 34px; margin-top: 6px; }
.detail-side p { margin-top: 8px; color: var(--text-2); }
.detail-side .tile-actions { justify-content: flex-start; margin-top: 22px; }
.detail-side dl { margin: 26px 0 0; display: grid; gap: 12px; }
.detail-side dt { font-size: 13px; color: var(--muted); }
.detail-side dd { margin: 2px 0 0; font-size: 15px; }
.detail-main h3 { font-size: 18px; margin-top: 28px; }
.detail-main h3:first-child { margin-top: 0; }
.detail-main ul { margin-top: 12px; display: grid; gap: 10px; }
.detail-main li { position: relative; padding-left: 26px; color: var(--text-2); }
.detail-main li::before { content: ""; position: absolute; left: 3px; top: 9px; width: 11px; height: 6px; border-left: 2px solid var(--ok); border-bottom: 2px solid var(--ok); transform: rotate(-45deg); }
.chapters { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-top: 14px; }
.chapters li { padding: 18px 20px 18px 20px !important; border-radius: 16px; background: var(--mist); }
.chapters li::before { display: none; }
.chapters b { display: block; color: var(--text); margin-bottom: 4px; }

.steps-bar { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; margin-top: 26px; }
.steps-bar span { font-size: 14px; padding: 6px 14px; border-radius: 999px; border: 1px solid var(--line-dark); color: var(--on-dark-2); }
.steps-bar span.on { background: var(--gold); border-color: var(--gold); color: #1a1205; font-weight: 700; }
.enroll-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 40px; align-items: start; padding-block: 64px 96px; }
.pay-box { padding: 30px; border-radius: var(--radius); background: var(--mist); }
.pay-box h3 { font-size: 20px; }
.pay-box p { margin-top: 8px; color: var(--text-2); font-size: 15px; }
.pay-list { display: grid; gap: 12px; margin-top: 18px; }
.pay-item { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 16px 18px; border-radius: 14px; background: #fff; border: 1px solid var(--line); }
.pay-item b { font-size: 16px; }
.pay-item small { display: block; color: var(--muted); font-size: 13px; }
.done-box { display: none; padding: 32px; border-radius: var(--radius); background: #fff; border: 1px solid var(--line); text-align: center; }
.done-box.show { display: block; }
.done-box .big-ck { width: 64px; height: 64px; margin: 0 auto; border-radius: 50%; background: var(--ok); color: #fff; display: grid; place-items: center; font-size: 30px; font-weight: 800; }
.done-box h3 { margin-top: 16px; font-size: 24px; }
.done-box p { margin-top: 8px; color: var(--text-2); }

.files { display: grid; gap: 12px; padding-block: 56px 96px; }
.file-row { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 18px 22px; border-radius: 16px; border: 1px solid var(--line); background: #fff; }
.file-row b { display: block; font-size: 16px; }
.file-row small { color: var(--muted); font-size: 13px; }
.empty { text-align: center; padding: 48px 20px; color: var(--muted); border: 1.5px dashed var(--line); border-radius: 18px; }

/* ---------- 第一批新增：最近开班、隐私同意、发票、提取码、正文页 ---------- */
.sr { position: absolute !important; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.tile-next {
  display: inline-block; margin-top: 14px; padding: 6px 14px; border-radius: 999px; font-size: 14px; font-weight: 600;
  color: var(--gold-ink); background: rgba(244, 183, 64, .16);
}
.tile-dark .tile-next { color: var(--gold); background: rgba(244, 183, 64, .14); }
.cmp-next { margin-top: 6px; font-size: 13px; color: var(--gold-ink); font-weight: 600; }
.consent { display: flex; gap: 8px; align-items: flex-start; font-size: 13.5px; color: var(--text-2); line-height: 1.5; cursor: pointer; }
.consent input { margin-top: 3px; width: 16px; height: 16px; flex-shrink: 0; accent-color: var(--text); }
.consent a, .form-privacy a { color: var(--gold-ink); text-decoration: underline; }
.check-line { display: flex; align-items: center; gap: 8px; font-size: 15px; color: var(--text-2); cursor: pointer; }
.check-line input { width: 16px; height: 16px; accent-color: var(--text); }
.invoice-box { display: grid; gap: 14px; padding: 16px; border-radius: 14px; background: var(--mist); }
.invoice-box .field input { background: #fff; }
.class-box { margin-top: 48px; padding: 28px; border-radius: var(--radius); background: var(--mist); }
.class-box h2, .files-title { font-size: 22px; }
.class-box > p { margin-top: 6px; color: var(--text-2); font-size: 15px; }
.code-form { display: flex; gap: 10px; margin-top: 16px; flex-wrap: wrap; }
.code-form input {
  flex: 1 1 200px; min-width: 0; font: inherit; font-family: var(--mono); font-size: 18px; letter-spacing: .2em; text-transform: uppercase;
  padding: 10px 14px; border-radius: 12px; border: 1.5px solid var(--line); background: #fff; color: var(--text);
}
.code-form input:focus { outline: none; border-color: var(--gold); }
.class-box .form-msg { margin-top: 10px; }
.class-box .files { padding-block: 16px 0; }
.files-title { margin-top: 48px; }
.wrap.narrow > .files { padding-block: 16px 96px; }
.prose { padding-block: 56px 96px; color: var(--text-2); font-size: 16px; line-height: 1.85; }
.prose h2 { margin-top: 36px; font-size: 20px; color: var(--text); }
.prose p { margin-top: 10px; }
.prose ul { margin-top: 10px; display: grid; gap: 6px; }
.prose ul li { position: relative; padding-left: 18px; }
.prose ul li::before { content: ""; position: absolute; left: 2px; top: 12px; width: 6px; height: 6px; border-radius: 50%; background: var(--gold); }
.prose .contact-items li::before { display: none; }
.prose .contact-items li { padding-left: 0; }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--mist); color: var(--muted); font-size: 13px; padding-block: 44px 36px; }
.foot-cols { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; padding-bottom: 28px; border-bottom: 1px solid var(--line); }
.foot-cols h4 { font-size: 13px; color: var(--text); margin-bottom: 10px; letter-spacing: 0; }
.foot-cols li + li { margin-top: 7px; }
.foot-cols a:hover { color: var(--text); text-decoration: underline; }
.foot-base { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 10px 24px; padding-top: 20px; }

/* ---------- 动效 ---------- */
@keyframes breathe { 0%, 100% { opacity: .85; transform: translateX(-50%) scale(1); } 50% { opacity: 1; transform: translateX(-50%) scale(1.06); } }
@keyframes float1 { 0%, 100% { translate: 0 0; } 50% { translate: 0 -10px; } }
@keyframes float2 { 0%, 100% { translate: 0 0; } 50% { translate: 0 -14px; } }
@keyframes float3 { 0%, 100% { translate: 0 -6px; } 50% { translate: 0 6px; } }
@keyframes blink { 50% { opacity: 0; } }
@keyframes sweep { from { background-size: 0% 100%; } to { background-size: 100% 100%; } }
@keyframes pop { from { transform: scale(.4); } 70% { transform: scale(1.12); } to { transform: scale(1); } }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

/* ---------- 响应式 ---------- */
@media (max-width: 980px) {
  .compare { grid-template-columns: 1fr; gap: 40px; }
  .cmp + .cmp { border-left: 0; border-top: 1px solid var(--line); padding-top: 40px; }
  .lead-wrap, .enroll-grid { grid-template-columns: 1fr; gap: 32px; }
  .detail { grid-template-columns: 1fr; gap: 24px; }
  .proof { grid-template-columns: 1fr; }
}
@media (max-width: 820px) {
  .site-nav {
    position: absolute; top: 56px; left: 0; right: 0; display: none;
    flex-direction: column; align-items: stretch; gap: 0;
    background: rgba(7, 8, 11, .96); border-bottom: 1px solid var(--line-dark);
    padding: 6px max(var(--gutter), env(safe-area-inset-right, 0px)) 18px max(var(--gutter), env(safe-area-inset-left, 0px));
  }
  .site-nav.open { display: flex; }
  .site-nav a { padding: 13px 2px; border-bottom: 1px solid var(--line-dark); font-size: 16px; }
  .site-nav .nav-cta { margin-top: 14px; text-align: center; border-bottom: 0; padding: 12px; }
  .nav-toggle { display: block; }
  .duo { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; }
  body { font-size: 16px; }
  .hero { padding-block: 60px 0; }
  .stack { height: 330px; margin-top: 44px; }
  .stack-card { width: 90%; height: 200px; padding: 18px 20px; bottom: -30px; animation: none; }
  .sc-name { font-size: 21px; margin-top: 4px; }
  .sc-2 .sc-name { font-size: 23px; }
  .sc-tag { font-size: 14px; }
  .sc-chips { margin-top: 14px; }
  .sc-1 { transform: translateX(-50%) translateY(-176px) scale(.9); z-index: 1; }
  .sc-2 { transform: translateX(-50%) translateY(-92px) scale(.95); z-index: 2; }
  .sc-3 { transform: translateX(-50%); z-index: 3; text-align: left; }
  .sc-3 .sc-chips { justify-content: flex-start; }
  .sc-1 .sc-tag, .sc-2 .sc-tag, .sc-1 .sc-chips, .sc-2 .sc-chips { display: none; }
  .tile { padding-block: 60px 0; }
  .tile-visual { margin-top: 40px; }
  .term { font-size: 12.5px; }
  .term-body { padding: 18px 16px 26px; }
  .manuscript { height: 380px; }
  .page { height: 340px; padding: 24px 22px; }
  .note { max-width: 180px; font-size: 12.5px; padding: 8px 11px; }
  .note-b { top: 170px; }
  .note-c { top: 270px; }
  .letter { padding: 22px 18px 28px; }
  .letter li { grid-template-columns: 58px 1fr 24px; gap: 8px; font-size: 14px; }
  .section { padding-block: 64px; }
  .form { padding: 22px 18px; }
  .form-row { grid-template-columns: 1fr; }
  .teacher-card { grid-template-columns: 1fr; padding: 24px 20px; }
  .avatar { width: 72px; height: 72px; font-size: 32px; border-radius: 20px; }
  .foot-cols { grid-template-columns: 1fr 1fr; }
  .chapters { grid-template-columns: 1fr; }
  .fab { height: 48px; padding: 0 16px; }
  .file-row { flex-direction: column; align-items: flex-start; }
}