:root {
  color-scheme: light;
  --paper:      oklch(0.97 0.008 85);
  --paper-band: oklch(0.945 0.012 80);
  --paper-card: oklch(0.99 0.004 85);
  --ink:        oklch(0.2 0.025 250);
  --ink-soft:   oklch(0.48 0.015 250);
  --ink-pale:   oklch(0.7 0.01 250);
  --rule:       oklch(0.85 0.005 250);
  --rule-soft:  oklch(0.92 0.004 250);
  --mark:       oklch(0.58 0.14 60);
  --mark-soft:  oklch(0.93 0.05 70);
  --ok:         oklch(0.62 0.13 145);
  --warn:       oklch(0.65 0.16 30);

  --f-body:    "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", system-ui, sans-serif;
  --f-serif:   "FangSong", "STFangsong", "PingFang SC", serif;
  --f-display: "PingFang SC", "Microsoft YaHei", "HeiTi SC", sans-serif;
  --f-mono:    "SF Mono", "JetBrains Mono", "Menlo", "Consolas", monospace;

  --sp-1: clamp(4px, 0.4vw, 6px);
  --sp-2: clamp(8px, 0.8vw, 12px);
  --sp-3: clamp(14px, 1.4vw, 20px);
  --sp-4: clamp(22px, 2.4vw, 32px);
  --sp-5: clamp(36px, 4vw, 56px);
  --sp-6: clamp(56px, 6.5vw, 96px);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { background: var(--paper); color: var(--ink); }
body {
  font-family: var(--f-body);
  font-size: 15px;
  line-height: 1.72;
  font-feature-settings: "tnum" 1;
  -webkit-font-smoothing: antialiased;
}

button { font: inherit; cursor: pointer; }
input, textarea, select { font: inherit; color: inherit; }
a { color: inherit; }

.app { min-height: 100vh; }

/* ---------- masthead ---------- */
.masthead {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--paper);
  border-bottom: 1px solid var(--ink);
  padding: var(--sp-2) var(--sp-4);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.masthead .brand-mark { color: var(--ink); font-weight: 700; }
.masthead .brand-sub { margin-left: var(--sp-3); }
.masthead .status > span { margin-left: var(--sp-3); }
.masthead .status-stage { color: var(--ink); }
.masthead .status-save.saving { color: var(--mark); }
.masthead .status-save.saved { color: var(--ok); }
.masthead .status-save.error { color: var(--warn); }

/* ---------- 3-col shell ---------- */
.shell {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr) 240px;
  max-width: 1320px;
  margin: 0 auto;
  gap: var(--sp-5);
  padding: var(--sp-4);
}

/* ---------- sidebar ---------- */
.sidebar {
  position: sticky;
  top: 48px;
  align-self: start;
  max-height: calc(100vh - 64px);
  overflow-y: auto;
  padding-right: var(--sp-2);
}
.sb-block + .sb-block { margin-top: var(--sp-4); }
.sb-stage {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ink-soft);
  text-transform: uppercase;
  border-bottom: 1px solid var(--ink);
  padding-bottom: var(--sp-2);
  margin-bottom: var(--sp-2);
}
.sb-nav { display: flex; flex-direction: column; gap: 1px; }
.sb-nav a {
  display: grid;
  grid-template-columns: 32px 1fr 18px;
  align-items: baseline;
  gap: 6px;
  padding: 6px 4px;
  text-decoration: none;
  border-radius: 2px;
  color: var(--ink-soft);
  font-size: 13.5px;
  line-height: 1.4;
  transition: background 0.12s;
}
.sb-nav a:hover { background: var(--paper-band); color: var(--ink); }
.sb-nav a.active { color: var(--ink); font-weight: 600; }
.sb-nav .sb-num {
  font-family: var(--f-mono);
  font-size: 11px;
  color: var(--ink-pale);
  letter-spacing: 0.04em;
}
.sb-nav a.active .sb-num,
.sb-nav a.touched .sb-num { color: var(--ink-soft); }
.sb-nav .sb-mark {
  font-family: var(--f-mono);
  font-size: 12px;
  text-align: right;
}
.sb-nav a.touched .sb-mark::before { content: ""; }
.sb-nav a.filled .sb-mark::before { content: "OK"; color: var(--ok); font-size: 10px; letter-spacing: 0.1em; }
.sb-nav a.active .sb-mark::before { content: ""; }
.sb-nav a.active::after {
  content: "";
  position: absolute;
}
.sb-locked {
  font-size: 12px;
  color: var(--ink-pale);
  padding: var(--sp-2);
  border: 1px dashed var(--rule);
  text-align: center;
  font-family: var(--f-serif);
}

.sb-foot {
  margin-top: var(--sp-4);
  padding-top: var(--sp-2);
  border-top: 1px solid var(--rule);
  font-family: var(--f-mono);
  font-size: 10.5px;
  color: var(--ink-soft);
  letter-spacing: 0.08em;
}
.sb-foot-row { display: flex; justify-content: space-between; padding: 2px 0; }
.sb-foot-row .mono { color: var(--ink); }

/* ---------- intro ---------- */
.intro { margin-bottom: var(--sp-5); }
.intro-overline {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin-bottom: var(--sp-2);
}
.intro h1 {
  font-family: var(--f-display);
  font-weight: 800;
  font-size: clamp(28px, 3.6vw, 40px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin-bottom: var(--sp-3);
}
.intro-lede {
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--ink-soft);
  max-width: 60ch;
  margin-bottom: var(--sp-3);
}
.intro-meta {
  font-family: var(--f-mono);
  font-size: 11px;
  color: var(--ink-soft);
  letter-spacing: 0.06em;
}
.intro-meta .dot {
  display: inline-block;
  width: 4px;
  height: 4px;
  background: var(--ink-pale);
  border-radius: 50%;
  vertical-align: 2px;
  margin: 0 2px;
}

/* ---------- section ---------- */
.sec {
  margin-bottom: var(--sp-5);
  padding-bottom: var(--sp-4);
  border-bottom: 1px solid var(--rule);
  scroll-margin-top: 64px;
}
.sec:last-of-type { border-bottom: none; }
.sec-h {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: var(--sp-3);
  align-items: baseline;
  border-bottom: 1px solid var(--ink);
  padding-bottom: var(--sp-2);
  margin-bottom: var(--sp-4);
}
.sec-num {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
}
.sec-num strong {
  display: block;
  font-family: var(--f-display);
  font-size: 26px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: -0.01em;
  margin-top: 2px;
}
.sec-h h2 {
  font-family: var(--f-display);
  font-weight: 700;
  font-size: clamp(20px, 2vw, 24px);
  margin-bottom: 2px;
}
.sec-desc {
  font-size: 13.5px;
  color: var(--ink-soft);
  max-width: 56ch;
}
.sec.tier-1 .sec-num strong { color: var(--ink); }
.sec.cond .sec-h::after,
.sec.skip .sec-h::after {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
  border: 1px solid var(--rule);
  padding: 2px 6px;
  align-self: center;
}
.sec.cond .sec-h::after { content: "条件"; }
.sec.skip .sec-h::after { content: "可跳过"; }

/* ---------- grid + fields ---------- */
.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--sp-3) var(--sp-4);
}
.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.f.wide { grid-column: 1 / -1; }

.f { display: flex; flex-direction: column; gap: 4px; }
.f label {
  font-family: var(--f-display);
  font-size: 13px;
  font-weight: 600;
  color: var(--ink);
  letter-spacing: 0.01em;
}
.f .hint {
  font-size: 12px;
  color: var(--ink-soft);
  line-height: 1.5;
  margin-top: 2px;
}

.f input[type="text"],
.f input[type="email"],
.f input[type="tel"],
.f input[type="number"],
.f textarea,
.f select {
  background: var(--paper-card);
  border: 1px solid var(--rule);
  border-radius: 2px;
  padding: 9px 12px;
  font-size: 14.5px;
  line-height: 1.5;
  color: var(--ink);
  transition: border-color 0.12s, background 0.12s;
  width: 100%;
}
.f input:focus,
.f textarea:focus,
.f select:focus {
  outline: none;
  border-color: var(--ink);
  background: oklch(1 0 0);
}
.f textarea { resize: vertical; min-height: 80px; font-family: var(--f-body); }
.f input[type="number"] { font-variant-numeric: tabular-nums; max-width: 160px; }

/* color input */
.color-input {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 8px;
  align-items: center;
}
.color-input input[type="color"] {
  width: 44px;
  height: 38px;
  border: 1px solid var(--rule);
  background: var(--paper-card);
  padding: 2px;
  border-radius: 2px;
  cursor: pointer;
}
.color-input input[type="text"] {
  font-family: var(--f-mono);
  text-transform: uppercase;
}

/* suffix input (email prefix) */
.suffix-input {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: stretch;
  border: 1px solid var(--rule);
  border-radius: 2px;
  background: var(--paper-card);
}
.suffix-input input {
  border: none !important;
  background: transparent !important;
  padding: 9px 12px !important;
}
.suffix-input .suffix {
  padding: 0 12px;
  display: flex;
  align-items: center;
  color: var(--ink-soft);
  font-family: var(--f-mono);
  font-size: 13.5px;
  border-left: 1px solid var(--rule);
  background: var(--paper-band);
}

/* radio row */
.radio-row { display: flex; gap: var(--sp-3); align-items: center; padding-top: 6px; }
.radio-row label {
  display: flex;
  gap: 6px;
  align-items: center;
  font-weight: 400;
  font-size: 14px;
  cursor: pointer;
}
.radio-row input[type="radio"] {
  width: 16px;
  height: 16px;
  accent-color: var(--ink);
}

/* ---------- dynamic list ---------- */
.dyn-list { display: flex; flex-direction: column; gap: var(--sp-3); margin-top: var(--sp-2); }
.dyn-row {
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
  padding: var(--sp-3);
  background: var(--paper-band);
  border: 1px solid var(--rule);
  border-radius: 2px;
  position: relative;
}
.dyn-row.sub { background: transparent; border: none; padding: 0; }
.dyn-row.card {
  background: var(--paper-card);
  padding: var(--sp-3) var(--sp-4);
}
.card-h {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  border-bottom: 1px solid var(--rule);
  padding-bottom: 8px;
  margin-bottom: 8px;
}
.card-idx {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ink-soft);
  text-transform: uppercase;
}
.add-btn {
  margin-top: var(--sp-3);
  background: transparent;
  border: 1px dashed var(--ink);
  border-radius: 2px;
  padding: 8px 16px;
  font-size: 13px;
  color: var(--ink);
  font-family: var(--f-display);
  letter-spacing: 0.04em;
}
.add-btn:hover { background: var(--paper-band); }
.del-btn {
  background: transparent;
  border: none;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--ink-soft);
  text-transform: uppercase;
  padding: 4px 8px;
}
.del-btn:hover { color: var(--warn); }

/* ---------- upload ---------- */
.upload-f .upload-zone {
  border: 1px dashed var(--rule);
  background: var(--paper-card);
  padding: var(--sp-3);
  border-radius: 2px;
  transition: border-color 0.15s, background 0.15s;
}
.upload-f .upload-zone.drag {
  border-color: var(--ink);
  background: var(--paper-band);
}
.up-drop {
  text-align: center;
  font-size: 13.5px;
  color: var(--ink-soft);
  padding: var(--sp-2);
}
.up-pick {
  background: transparent;
  border: 1px solid var(--ink);
  color: var(--ink);
  padding: 4px 12px;
  margin-left: 6px;
  border-radius: 2px;
  font-size: 13px;
}
.up-pick:hover { background: var(--ink); color: var(--paper); }
.up-list { list-style: none; margin: var(--sp-2) 0 0 0; padding: 0; display: flex; flex-direction: column; gap: 6px; }
.up-list li {
  display: grid;
  grid-template-columns: 40px 1fr auto auto;
  gap: 8px;
  align-items: center;
  background: var(--paper-band);
  padding: 6px 10px;
  border-radius: 2px;
  font-size: 13px;
}
.up-list li .up-thumb {
  width: 40px;
  height: 40px;
  background: var(--rule-soft);
  border-radius: 2px;
  background-size: cover;
  background-position: center;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--f-mono);
  font-size: 10px;
  color: var(--ink-soft);
}
.up-list li .up-name {
  font-family: var(--f-body);
  color: var(--ink);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.up-list li .up-size {
  font-family: var(--f-mono);
  font-size: 11px;
  color: var(--ink-soft);
  white-space: nowrap;
}
.up-list li .up-remove {
  background: transparent;
  border: none;
  color: var(--ink-soft);
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.up-list li .up-remove:hover { color: var(--warn); }
.up-list li.uploading { opacity: 0.7; }
.up-list li.error { background: oklch(0.93 0.05 30); }
.up-progress {
  grid-column: 1 / -1;
  height: 2px;
  background: var(--rule);
  border-radius: 1px;
  overflow: hidden;
}
.up-progress > i {
  display: block;
  height: 100%;
  background: var(--ink);
  width: 0;
  transition: width 0.2s;
}

/* ---------- submit bar ---------- */
.submit-bar {
  margin: var(--sp-5) 0;
  padding: var(--sp-4);
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--sp-4);
  align-items: center;
  background: var(--paper-card);
}
.sb-left .sb-title {
  font-family: var(--f-display);
  font-weight: 700;
  font-size: 18px;
  margin-bottom: 4px;
}
.sb-left .sb-note {
  font-size: 13px;
  color: var(--ink-soft);
  max-width: 50ch;
}
.submit-bar .primary {
  background: var(--ink);
  color: var(--paper);
  border: none;
  padding: 12px 22px;
  font-family: var(--f-display);
  font-weight: 600;
  font-size: 14px;
  letter-spacing: 0.04em;
  border-radius: 2px;
  white-space: nowrap;
}
.submit-bar .primary:hover { background: oklch(0.32 0.04 250); }
.submit-bar .primary[disabled] { opacity: 0.5; cursor: not-allowed; }

/* ---------- stage 2 marker ---------- */
.stage2-marker {
  margin: var(--sp-6) 0 var(--sp-4);
  padding: var(--sp-4);
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  background: var(--paper-band);
}
.stage2-marker .overline {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin-bottom: 6px;
}
.stage2-marker h2 {
  font-family: var(--f-display);
  font-weight: 700;
  font-size: 22px;
  margin-bottom: 4px;
}
.stage2-marker p { font-size: 14px; color: var(--ink-soft); }

/* ---------- context panel ---------- */
.ctx {
  position: sticky;
  top: 48px;
  align-self: start;
  max-height: calc(100vh - 64px);
  overflow-y: auto;
}
.ctx-tag {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-soft);
  border-bottom: 1px solid var(--ink);
  padding-bottom: 6px;
  margin-bottom: var(--sp-3);
}
.ctx-body {
  font-size: 13px;
  color: var(--ink-soft);
  line-height: 1.7;
}
.ctx-body p { margin-bottom: var(--sp-2); }
.ctx-body strong { color: var(--ink); font-weight: 600; }
.ctx-body code {
  font-family: var(--f-mono);
  background: var(--paper-band);
  padding: 1px 5px;
  font-size: 12px;
}

/* ---------- footer ---------- */
.page-foot {
  margin-top: var(--sp-6);
  padding-top: var(--sp-3);
  border-top: 1px solid var(--ink);
  display: flex;
  justify-content: space-between;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

/* ---------- toast ---------- */
.toast-host {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 100;
  display: flex;
  flex-direction: column;
  gap: 8px;
  pointer-events: none;
}
.toast {
  background: var(--ink);
  color: var(--paper);
  padding: 10px 16px;
  border-radius: 2px;
  font-size: 13px;
  font-family: var(--f-mono);
  letter-spacing: 0.04em;
  box-shadow: 0 4px 24px oklch(0 0 0 / 0.15);
  pointer-events: auto;
  animation: tin 0.18s ease-out;
}
.toast.ok { background: var(--ok); }
.toast.warn { background: var(--warn); }
@keyframes tin { from { transform: translateY(8px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

/* ---------- responsive ---------- */
@media (max-width: 1080px) {
  .shell { grid-template-columns: 200px minmax(0, 1fr); }
  .ctx { display: none; }
}
@media (max-width: 760px) {
  .shell { grid-template-columns: 1fr; padding: var(--sp-3); gap: var(--sp-3); }
  .sidebar {
    position: static;
    max-height: none;
    overflow: visible;
    margin-bottom: var(--sp-3);
  }
  .sb-nav { flex-direction: row; flex-wrap: wrap; gap: 6px; }
  .sb-nav a { grid-template-columns: auto auto auto; padding: 6px 10px; border: 1px solid var(--rule); border-radius: 2px; }
  .sb-foot { display: none; }
  .sec-h { grid-template-columns: 60px 1fr; }
  .sec-num strong { font-size: 20px; }
  .grid { grid-template-columns: 1fr; }
  .grid-3 { grid-template-columns: 1fr; }
  .submit-bar { grid-template-columns: 1fr; }
}