:root {
  color-scheme: light;
  --bg: #f4f6fb;
  --card: #ffffff;
  --ink: #1f2430;
  --muted: #6b7280;
  --line: #e5e8f0;
  --brand: #4f6ef7;
  --brand-2: #7a5cf0;
  --grad: linear-gradient(135deg, #4f6ef7, #7a5cf0);
  --ok: #10b981;
  --chip: #eef1ff;
  --field: #fafbff;
  --head-grad: linear-gradient(180deg, #fafbff, #fff);
  --dash: #eef1f7;
  --faint: #9aa3b5;
  --empty-line: #cfd6e6;
  --radius: 16px;
  --shadow: 0 8px 30px rgba(31, 41, 80, .08);
}

/* Dark theme (explicit) */
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0e1220;
  --card: #1a1f33;
  --ink: #e8eaf5;
  --muted: #9aa3bb;
  --line: #2b3252;
  --chip: #232a49;
  --field: #151a2d;
  --head-grad: linear-gradient(180deg, #1d2238, #1a1f33);
  --dash: #262d4a;
  --faint: #7c84a1;
  --empty-line: #343c60;
  --shadow: 0 8px 30px rgba(0, 0, 0, .38);
}
/* Follow system: dark */
@media (prefers-color-scheme: dark) {
  :root[data-theme="system"] {
    color-scheme: dark;
    --bg: #0e1220;
    --card: #1a1f33;
    --ink: #e8eaf5;
    --muted: #9aa3bb;
    --line: #2b3252;
    --chip: #232a49;
    --field: #151a2d;
    --head-grad: linear-gradient(180deg, #1d2238, #1a1f33);
    --dash: #262d4a;
    --faint: #7c84a1;
    --empty-line: #343c60;
    --shadow: 0 8px 30px rgba(0, 0, 0, .38);
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; }
body {
  font-family: "Inter", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.5;
  min-height: 100vh;
}
.app { max-width: 1100px; margin: 0 auto; padding: 24px 16px 60px; }

/* Hero */
.hero { margin-bottom: 20px; }
.hero-inner { display: flex; flex-direction: column; gap: 18px; }
.top { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }

/* Theme switch */
.theme-control {
  display: inline-flex;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 4px;
  box-shadow: var(--shadow);
  gap: 2px;
}
.theme-control .th {
  border: none;
  background: transparent;
  color: var(--muted);
  font-size: 12.5px;
  font-weight: 600;
  font-family: inherit;
  padding: 7px 12px;
  border-radius: 999px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  transition: background .15s, color .15s, box-shadow .15s;
}
.theme-control .th span { font-size: 13px; }
.theme-control .th:hover { color: var(--ink); }
.theme-control .th.active {
  background: var(--grad);
  color: #fff;
  box-shadow: 0 3px 10px rgba(79,110,247,.35);
}

.brand { display: flex; align-items: center; gap: 14px; }
.brand-mark {
  font-size: 34px;
  width: 58px; height: 58px;
  display: grid; place-items: center;
  background: var(--grad); border-radius: 16px;
  box-shadow: var(--shadow); flex: none;
}
.brand-text h1 { font-size: 26px; font-weight: 800; letter-spacing: .2px; }
.brand-text p { color: var(--muted); font-size: 13.5px; margin-top: 2px; }

/* Controls */
.controls {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 16px;
  display: grid;
  gap: 14px;
  grid-template-columns: 1fr 1fr;
}
.field { display: flex; flex-direction: column; gap: 6px; }
.field label { font-size: 12px; font-weight: 600; color: var(--muted); text-transform: uppercase; letter-spacing: .4px; }
.field select,
.field input {
  appearance: none;
  -webkit-appearance: none;
  border: 1px solid var(--line);
  background: var(--field);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 14px;
  color: var(--ink);
  font-family: inherit;
  transition: border-color .15s, box-shadow .15s;
}
.field select { cursor: pointer; }
.field select:focus, .field input:focus {
  outline: none;
  border-color: var(--brand);
  box-shadow: 0 0 0 3px rgba(79,110,247,.15);
}
.field-qty { grid-column: span 2; }

.btn-primary {
  grid-column: span 2;
  border: none;
  background: var(--grad);
  color: #fff;
  font-weight: 700;
  font-size: 15px;
  padding: 12px 16px;
  border-radius: 12px;
  cursor: pointer;
  letter-spacing: .2px;
  box-shadow: 0 8px 20px rgba(79,110,247,.35);
  transition: transform .1s, box-shadow .15s, filter .15s;
}
.btn-primary:hover { filter: brightness(1.05); box-shadow: 0 10px 26px rgba(79,110,247,.42); }
.btn-primary:active { transform: translateY(1px); }
.btn-primary i { font-style: normal; font-weight: 500; opacity: .75; font-size: 12.5px; margin-left: 6px; }

/* Options chip bar */
.options {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 18px 0 18px;
}
.opt-chip {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 7px 12px;
  font-size: 13px;
  color: var(--muted);
  box-shadow: 0 2px 8px rgba(31,41,80,.05);
}
.opt-chip b { color: var(--ink); font-weight: 600; }
.opt-chip .tag { font-size: 11px; background: var(--chip); color: var(--brand); padding: 2px 8px; border-radius: 999px; font-weight: 600; }

/* Toolbar */
.toolbar {
  grid-column: span 2;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin-top: 18px;
  flex-wrap: wrap;
}
.toolbar-info { font-size: 13.5px; color: var(--muted); }
.toolbar-info b { color: var(--ink); }
.result-actions { display: flex; gap: 8px; flex-wrap: wrap; }
.btn-ghost {
  background: var(--card);
  border: 1px solid var(--line);
  color: var(--ink);
  font-size: 13px;
  font-weight: 600;
  padding: 8px 14px;
  border-radius: 10px;
  cursor: pointer;
  font-family: inherit;
  transition: border-color .15s, background .15s;
}
.btn-ghost:hover { border-color: var(--brand); color: var(--brand); background: #f8f9ff; }

/* Cards */
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 22px;
  overflow: hidden;
}
.card-head {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--line);
  background: var(--head-grad);
}
.card-index {
  width: 30px; height: 30px;
  border-radius: 9px;
  background: var(--grad);
  color: #fff;
  font-weight: 700;
  font-size: 14px;
  display: grid; place-items: center;
  flex: none;
}
.card-count{ margin-left:auto; font-size:12px; color:var(--muted); }

.grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0;
}
.card-body { padding: 4px 18px 14px; }

.section-h {
  display: flex; align-items: center; gap: 8px;
  font-size: 12.5px; font-weight: 700; color: var(--brand);
  text-transform: uppercase; letter-spacing: .6px;
  margin: 14px 0 6px;
}
.section-h::after { content: ""; flex: 1; height: 1px; background: var(--line); }

.row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding: 7px 0;
  border-bottom: 1px dashed var(--dash);
}
.row:last-child { border-bottom: none; }
.row .k { font-size: 13px; color: var(--muted); flex: none; max-width: 44%; }
.row .v {
  font-size: 13.5px; font-weight: 500;
  text-align: right;
  word-break: break-all;
  display: inline-flex; align-items: center; gap: 6px;
  justify-content: flex-end;
  max-width: 56%;
  cursor: pointer;
  border-radius: 6px;
  padding: 1px 4px;
  margin: -1px -4px;
  transition: color .12s;
}
.row .v:hover { color: var(--brand); }
.row .v:hover .copy-btn { opacity: 1; }
.row .copy-btn { opacity: .55; }
.row .v .sub { font-size: 11.5px; color: var(--muted); font-weight: 400; }
.copy-btn {
  border: none; background: transparent; color: var(--faint);
  cursor: pointer; font-size: 13px; padding: 2px 4px; border-radius: 6px;
  line-height: 1; transition: color .15s, background .15s;
}
.copy-btn:hover { color: var(--brand); background: var(--chip); }
.v:hover .copy-btn, .copy-btn:hover { color: var(--brand); }

/* Email link */
a.mail { color: var(--brand); font-weight: 600; text-decoration: none; }
a.mail:hover { text-decoration: underline; }
.mail-hint {
  display: inline-block; margin-top: 4px;
  font-size: 11.5px; color: var(--muted);
  background: var(--chip); padding: 2px 8px; border-radius: 999px;
  margin-left: 6px;
}

/* Empty state */
.empty {
  text-align: center;
  padding: 80px 20px;
  color: var(--muted);
  background: var(--card);
  border: 1px dashed var(--empty-line);
  border-radius: var(--radius);
}
.empty .big { font-size: 44px; margin-bottom: 12px; }
.empty p { max-width: 460px; margin: 8px auto; font-size: 14px; }

/* Toast */
.toast {
  position: fixed;
  bottom: 24px; left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: #161b27;
  color: #fff;
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 13.5px;
  opacity: 0;
  pointer-events: none;
  transition: opacity .25s, transform .25s;
  z-index: 60;
  box-shadow: 0 8px 24px rgba(0,0,0,.25);
  white-space: nowrap;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

.foot { text-align: center; color: var(--faint); font-size: 12.5px; margin-top: 20px; }

/* Responsive */
@media (max-width: 640px) {
  .app { padding: 16px 12px 50px; }
  .brand-mark { width: 48px; height: 48px; font-size: 26px; border-radius: 13px; }
  .brand-text h1 { font-size: 21px; }
  .controls { grid-template-columns: 1fr; padding: 14px; }
  .field-qty { grid-column: span 1; }
  .btn-primary { grid-column: span 1; }
  .grid { grid-template-columns: 1fr; }
  .row .k { max-width: 46%; }
  .toolbar { flex-direction: column; align-items: flex-start; }
  .toast { white-space: normal; max-width: 86vw; text-align: center; }
}
@media (min-width: 640px) and (max-width: 860px) {
  .controls { grid-template-columns: 1fr 1fr; }
  .grid { grid-template-columns: 1fr; }
}

@media (min-width: 1000px) {
  .results { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; align-items: start; }
  .results .card { margin-bottom: 0; }
  .results .toolbar { grid-column: 1 / -1; }
  .results .empty { grid-column: 1 / -1; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}