/* ============================================================
 * 共创班页：朋友圈长图的网页版
 * 深灰底、衬线标题、发丝线、大数字。招生与历史共用。
 * ============================================================ */

:root {
  --bg: #47494b;
  --bg-deep: #3a3c3e;
  --ink: #e5e5e5;
  --muted: rgba(229, 229, 229, 0.62);
  --faint: rgba(229, 229, 229, 0.45);
  --line: rgba(255, 255, 255, 0.18);
  --line-soft: rgba(255, 255, 255, 0.12);
  --paper: #e5e5e5;
  --paper-ink: #1a1a1a;
  --paper-muted: #5c5e60;
  --serif: "Noto Serif SC", "Songti SC", serif;
  --sans: Inter, "PingFang SC", "Microsoft YaHei", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-weight: 300;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
::selection { background: var(--paper); color: var(--paper-ink); }

.wrap {
  width: min(1080px, calc(100% - 48px));
  margin: 0 auto;
}

.sec {
  position: relative;
  padding: 88px 0;
  border-top: 1px solid var(--line);
  overflow: hidden;
  scroll-margin-top: 84px;
}

.wm {
  position: absolute;
  font-family: var(--serif);
  font-weight: 900;
  line-height: 0.78;
  color: rgba(255, 255, 255, 0.05);
  user-select: none;
  pointer-events: none;
}

/* ---------- mast ---------- */

.mast {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(71, 73, 75, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(16px);
}

.mast-inner {
  width: min(1080px, calc(100% - 48px));
  margin: 0 auto;
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex: none;
}

.brand b {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 22px;
  letter-spacing: 0.2em;
}

.brand i {
  font-style: normal;
  font-size: 13px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
}

.mast-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.cohorts {
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.cohorts a {
  font-family: var(--serif);
  font-size: 16px;
  letter-spacing: 0.12em;
  color: var(--faint);
  padding: 6px 14px 8px;
  border-bottom: 1px solid transparent;
}

.cohorts a.on,
.cohorts a[aria-current="page"] {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

.mast-nav .ghost {
  font-size: 14px;
  color: var(--muted);
  padding: 8px 10px;
}

.mast-nav .ghost:hover,
.cohorts a:hover { color: #fff; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 22px;
  border: 1px solid var(--ink);
  font-size: 15px;
  font-weight: 400;
  letter-spacing: 0.04em;
  transition: background 0.15s, color 0.15s;
}

.btn:hover { background: #fff; color: var(--paper-ink); }

.btn-solid {
  background: var(--paper);
  color: var(--paper-ink);
  border-color: var(--paper);
}

.btn-solid:hover { background: #fff; }

.btn-ink {
  background: var(--bg);
  color: var(--ink);
  border-color: var(--bg);
}

.btn-ink:hover { background: #2f3133; color: #fff; }

/* ---------- kicker / type ---------- */

.kicker {
  display: flex;
  align-items: baseline;
  gap: 18px;
  margin-bottom: 28px;
}

.kicker .no {
  font-family: var(--serif);
  font-size: 22px;
  color: var(--faint);
}

.kicker .en {
  font-size: 13px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--faint);
}

h1, h2, .serif { font-family: var(--serif); }

h1 {
  margin: 0;
  font-weight: 900;
  font-size: clamp(40px, 7vw, 88px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

h2 {
  margin: 0;
  font-weight: 700;
  font-size: clamp(32px, 5vw, 64px);
  line-height: 1.22;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.lede {
  margin: 28px 0 0;
  max-width: 40em;
  font-size: clamp(18px, 2vw, 22px);
  font-weight: 300;
  line-height: 1.8;
  color: var(--muted);
  text-wrap: pretty;
}

.italic {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 500;
  color: var(--ink);
}

.pills {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.pill {
  font-family: var(--serif);
  font-size: 15px;
  border: 1px solid rgba(229, 229, 229, 0.55);
  border-radius: 9999px;
  padding: 6px 16px;
}

.pill-strong {
  font-weight: 700;
  border: 0;
  padding: 0;
  font-size: 18px;
}

.dot {
  width: 1px;
  height: 18px;
  background: rgba(255, 255, 255, 0.4);
}

/* ---------- hero ---------- */

.hero {
  position: relative;
  overflow: hidden;
  min-height: calc(100vh - 72px);
  display: flex;
  flex-direction: column;
}

.hero .wm {
  top: 80px;
  right: -80px;
  font-size: clamp(220px, 42vw, 620px);
}

.hero-body {
  position: relative;
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 64px 0 0;
}

.hero h1 { margin-top: 36px; max-width: 16em; }

.hero .sub {
  margin: 28px 0 0;
  max-width: 18em;
  font-family: var(--serif);
  font-style: italic;
  font-weight: 500;
  font-size: clamp(24px, 3.4vw, 40px);
  line-height: 1.4;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 36px;
}

.hero-foot {
  position: relative;
  margin-top: auto;
  padding: 28px 0 40px;
  border-top: 1px solid var(--line);
  display: flex;
  align-items: baseline;
  gap: 28px;
  flex-wrap: wrap;
  font-size: 18px;
}

.hero-foot b {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 22px;
}

.proof {
  margin: 0;
  max-width: 42em;
  font-size: 16px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- lists ---------- */

.rule {
  margin-top: 44px;
  border-top: 1px solid var(--line);
}

.rule-row {
  display: flex;
  align-items: baseline;
  gap: 24px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.rule-row .dash {
  flex: none;
  width: 22px;
  height: 1px;
  background: rgba(229, 229, 229, 0.5);
  transform: translateY(-10px);
}

.rule-row .idx {
  flex: none;
  width: 2em;
  font-family: var(--serif);
  font-size: 20px;
  color: var(--faint);
}

.rule-row p,
.rule-row span {
  margin: 0;
  font-size: clamp(18px, 2vw, 24px);
  font-weight: 300;
  line-height: 1.5;
}

.rule-row .more {
  display: block;
  margin-top: 8px;
  font-size: 16px;
  color: var(--muted);
}

.note {
  margin: 40px 0 0;
  max-width: 42em;
  font-size: clamp(20px, 2.2vw, 28px);
  line-height: 1.6;
  text-wrap: pretty;
}

.prose {
  margin: 24px 0 0;
  max-width: 42em;
  font-size: 18px;
  line-height: 1.85;
  color: var(--muted);
  text-wrap: pretty;
}

/* ---------- stats / grids ---------- */

.stats {
  margin-top: 44px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.stat { padding: 28px 24px 28px 0; }
.stat + .stat { border-left: 1px solid var(--line); padding-left: 24px; }

.stat b {
  display: block;
  font-family: var(--serif);
  font-weight: 900;
  font-size: clamp(48px, 6vw, 72px);
  line-height: 1;
}

.stat span {
  display: block;
  margin-top: 10px;
  font-size: 16px;
  font-weight: 300;
  color: var(--muted);
}

.products {
  margin-top: 40px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px 18px;
}

.product { color: inherit; }

.product .shot {
  aspect-ratio: 1;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: var(--bg-deep);
}

.product img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
}

.product .cap {
  margin-top: 10px;
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex-wrap: wrap;
}

.product .cap b {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 17px;
}

.product .cap i {
  font-style: normal;
  font-size: 13px;
  font-weight: 300;
  color: var(--faint);
}

.product .one {
  margin: 6px 0 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

.product[href]:hover .cap b { text-decoration: underline; text-underline-offset: 4px; }

.weeks { margin-top: 44px; border-top: 1px solid var(--line); }

.week {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 28px;
  padding: 26px 0;
  border-bottom: 1px solid var(--line);
}

.week .w {
  font-family: var(--mono);
  font-size: 15px;
  letter-spacing: 0.1em;
  color: var(--faint);
  padding-top: 6px;
}

.week h3 {
  margin: 0;
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(22px, 2.4vw, 30px);
  line-height: 1.3;
}

.week p {
  margin: 8px 0 0;
  font-size: 17px;
  color: var(--muted);
}

.cells {
  margin-top: 44px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-top: 1px solid var(--line);
}

.cell {
  padding: 26px 24px 26px 0;
  border-bottom: 1px solid var(--line);
  font-size: 20px;
  font-weight: 300;
}

.cell:nth-child(even) {
  border-left: 1px solid var(--line);
  padding-left: 24px;
  padding-right: 0;
}

.box {
  margin-top: 40px;
  border: 1px solid var(--line);
  padding: 28px 32px;
}

.box .en {
  font-size: 13px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--faint);
}

.box p {
  margin: 14px 0 0;
  font-size: 18px;
  font-weight: 300;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- host / price / faq ---------- */

.host {
  margin-top: 40px;
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 28px;
  align-items: start;
}

.host img {
  width: 120px;
  height: 120px;
  object-fit: cover;
  border: 1px solid var(--line);
}

.host .name {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 28px;
}

.host .name span {
  margin-left: 12px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--faint);
}

.host .works {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 18px;
}

.host .works a,
.host .works span {
  font-family: var(--serif);
  font-size: 14px;
  border: 1px solid var(--line);
  padding: 6px 12px;
}

.host .works a:hover { background: var(--paper); color: var(--paper-ink); }

.price-grid {
  margin-top: 40px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.price { padding: 32px 28px 32px 0; }
.price + .price { border-left: 1px solid var(--line); padding-left: 28px; }

.price .en {
  font-size: 13px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--faint);
}

.price b {
  display: block;
  margin-top: 12px;
  font-family: var(--serif);
  font-weight: 900;
  font-size: clamp(44px, 6vw, 64px);
  line-height: 1;
}

.price.std b {
  font-weight: 500;
  color: var(--muted);
}

.info {
  margin-top: 28px;
  display: grid;
  gap: 0;
}

.info-row {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 20px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line-soft);
}

.info-row .k {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--faint);
  padding-top: 4px;
}

.info-row .v { font-size: 17px; }

.faq { margin-top: 36px; border-top: 1px solid var(--line); }

.faq details {
  border-bottom: 1px solid var(--line);
  padding: 18px 0;
}

.faq summary {
  cursor: pointer;
  list-style: none;
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 500;
  line-height: 1.4;
}

.faq summary::-webkit-details-marker { display: none; }

.faq summary::after {
  content: "+";
  float: right;
  font-family: var(--serif);
  color: var(--faint);
}

.faq details[open] summary::after { content: "–"; }

.faq details p {
  margin: 14px 0 0;
  max-width: 42em;
  font-size: 17px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- cta band / foot ---------- */

.cta {
  margin: 64px 0 0;
  background: #f3f3f2;
  color: #1a1a1a;
  padding: 56px 24px;
}

.cta-inner {
  width: min(1080px, 100%);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 56px;
  align-items: center;
}

.cta .en {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: #6f7376;
}

.cta h2 {
  margin: 14px 0 0;
  font-size: clamp(30px, 4vw, 44px);
  color: #1a1a1a;
}

.cta p {
  margin: 16px 0 0;
  max-width: 32em;
  font-size: 16px;
  line-height: 1.75;
  color: #3d4043;
}

.cta .sign {
  margin-top: 28px;
  padding-top: 22px;
  border-top: 1px solid rgba(26, 26, 26, 0.12);
}

.cta .sign .italic {
  color: #2f3133;
  font-size: 18px;
  line-height: 1.55;
}

.cta .sign .url {
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: #6f7376;
}

.qr-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  padding: 18px 18px 16px;
  background: #fff;
  border: 1px solid rgba(26, 26, 26, 0.12);
}

.qr-card img { width: 168px; height: 168px; }

.qr-card span {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: #6f7376;
}

.cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.cta-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 13px 22px;
  background: #1a1a1a;
  color: #f4f4f4;
  border: 1px solid #1a1a1a;
  font-size: 15px;
  letter-spacing: 0.04em;
}

.cta-btn:hover { background: #000; color: #fff; }

.cta-btn-ghost {
  background: transparent;
  color: #1a1a1a;
  border-color: #1a1a1a;
}

.cta-btn-ghost:hover {
  background: #1a1a1a;
  color: #f4f4f4;
}

.foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  flex-wrap: wrap;
  padding: 22px 0 28px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--faint);
}

.foot b {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 15px;
  letter-spacing: 0.08em;
  text-transform: none;
  color: var(--ink);
}

.foot a:hover { color: var(--ink); }

.home-fab {
  position: fixed;
  right: 22px;
  bottom: 22px;
  z-index: 50;
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  padding: 12px 20px;
  background: #1a1a1a;
  color: var(--ink);
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  border-radius: 999px;
}

.home-fab:hover { background: #000; }

/* ---------- archive ---------- */

.banner {
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  font-size: 14px;
}

.banner a {
  border-bottom: 1px solid rgba(229, 229, 229, 0.45);
  font-weight: 500;
}

.banner a:hover { border-bottom-color: #fff; }

/* ---------- mobile ---------- */

@media (max-width: 760px) {
  .wrap,
  .mast-inner { width: min(1080px, calc(100% - 32px)); }

  .mast-inner { min-height: 64px; }
  .brand i,
  .mast-nav .ghost { display: none; }

  .hero { min-height: auto; }
  .hero-body { padding-top: 40px; }
  .hero .wm { top: 20px; right: -40px; }
  .sec { padding: 56px 0; }

  .stats,
  .products,
  .cells,
  .price-grid,
  .cta-inner,
  .host { grid-template-columns: 1fr; }

  .stat + .stat,
  .cell:nth-child(even),
  .price + .price {
    border-left: 0;
    padding-left: 0;
    border-top: 1px solid var(--line);
  }

  .week { grid-template-columns: 1fr; gap: 8px; }
  .products { grid-template-columns: 1fr 1fr; gap: 22px 12px; }
  .info-row { grid-template-columns: 1fr; gap: 4px; }
  .cta { padding: 40px 16px; }
  .qr-card { justify-self: start; }
  .qr-card img { width: 148px; height: 148px; }
  .home-fab { right: 14px; bottom: 14px; }
  .banner { flex-direction: column; align-items: flex-start; gap: 8px; }
}