/* === Theme variables（与 codec 同款 light + dark，方便主题切换同步） === */
:root {
  color-scheme: light;
  --bg: #f5f3ef;
  --bg-deep: #ebe7df;
  --card: #fffdfa;
  --card-soft: #faf8f4;
  --text: #252524;
  --muted: #8b8984;
  --line: #e9e5de;
  --accent: #6572c7;
  --accent-soft: #eef0ff;
  --green: #4e9b7b;
  --warn: #c87a3a;
  --error: #c8443a;
  --shadow: 0 18px 55px rgba(75, 65, 50, 0.08);
  --radius: 22px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC", "Noto Sans SC", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Cascadia Code", monospace;
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #1d1e24;
  --bg-deep: #17181d;
  --card: #282930;
  --card-soft: #24252b;
  --text: #f1f0ec;
  --muted: #a1a0a0;
  --line: #3b3c44;
  --accent: #9ca7ff;
  --accent-soft: #30334b;
  --green: #79c3a1;
  --warn: #e0a264;
  --error: #e57872;
  --shadow: 0 18px 55px rgba(0, 0, 0, 0.18);
}

* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  font-family: var(--font);
  background: radial-gradient(circle at 4% 0%, rgba(218, 211, 193, 0.38), transparent 34%), var(--bg);
  transition: background 0.25s, color 0.25s;
}
body[data-theme="dark"] {
  background: radial-gradient(circle at 4% 0%, rgba(60, 80, 140, 0.22), transparent 36%), var(--bg);
}
button, input, textarea, select { font: inherit; }
button { cursor: pointer; }
textarea { font-family: var(--mono); }
.ambient { position: fixed; pointer-events: none; filter: blur(60px); opacity: 0.35; border-radius: 50%; z-index: -1; }
.ambient-one { width: 260px; height: 260px; background: #dfe4ff; top: 9%; right: 8%; }
.ambient-two { width: 220px; height: 220px; background: #f3ddca; bottom: 4%; left: 3%; }
body[data-theme="dark"] .ambient-one { background: #3e4a8a; opacity: 0.55; }
body[data-theme="dark"] .ambient-two { background: #5a3a30; opacity: 0.45; }

/* === Topbar === */
.topbar {
  height: 72px;
  padding: 0 clamp(20px, 4vw, 64px);
  display: flex; align-items: center; justify-content: space-between;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  backdrop-filter: blur(10px);
  position: sticky; top: 0; z-index: 5;
}
.back-link, .brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-size: 14px; }
.back-link { color: var(--muted); transition: color 0.2s; }
.back-link:hover { color: var(--accent); }
.brand { position: absolute; left: 50%; transform: translateX(-50%); font-weight: 700; letter-spacing: 0.01em; }
.brand-mark { color: var(--accent); font-size: 20px; }
.beta {
  border: 1px solid var(--line); border-radius: 99px;
  padding: 4px 7px; font-size: 8px; font-family: var(--mono);
  font-weight: 600; color: var(--muted);
}
.top-actions { display: flex; align-items: center; gap: 8px; }
.icon-button {
  border: 1px solid var(--line); background: var(--card); color: var(--muted);
  border-radius: 10px; width: 36px; height: 36px;
  transition: color 0.2s, border-color 0.2s;
}
.icon-button:hover { color: var(--accent); border-color: var(--accent); }

/* === Layout === */
.app-shell { width: min(1480px, calc(100% - 40px)); margin: 0 auto; padding: 48px 0 45px; }
.intro-row { display: flex; justify-content: space-between; align-items: flex-end; margin-bottom: 34px; gap: 20px; }
.eyebrow { color: var(--accent); font-size: 10px; letter-spacing: 0.16em; font-weight: 700; margin: 0 0 12px; }
.intro-row h1 { font-size: clamp(32px, 4vw, 52px); line-height: 1.12; letter-spacing: -0.05em; margin: 0; font-weight: 700; }
.intro-row h1 em { color: var(--accent); font-style: normal; }
.intro-copy { color: var(--muted); font-size: 15px; margin: 15px 0 0; line-height: 1.7; max-width: 60ch; }
.privacy-note { color: var(--green); display: flex; gap: 10px; align-items: flex-start; font-size: 12px; line-height: 1.5; padding-bottom: 4px; flex-shrink: 0; }
.privacy-note small { color: var(--muted); }
.privacy-dot {
  width: 7px; height: 7px; border-radius: 50%; background: var(--green);
  display: inline-block; margin-top: 5px;
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--green) 12%, transparent);
  flex-shrink: 0;
}

/* === Layout: 两栏（移动端上下） === */
.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 380px);
  gap: 18px;
  align-items: start;
}
@media (max-width: 880px) {
  .layout { grid-template-columns: 1fr; }
}

.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.panel { overflow: hidden; }
.surface-toolbar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 22px; border-bottom: 1px solid var(--line);
}
.surface-title h2 { font-size: 17px; margin: 6px 0 0; letter-spacing: -0.02em; }
.surface-title .label { font-size: 10px; letter-spacing: 0.16em; color: var(--muted); font-weight: 700; }
.surface-actions { display: flex; align-items: center; gap: 8px; }
.text-button {
  border: 0; background: transparent; color: var(--muted);
  padding: 6px 10px; font-size: 12px; border-radius: 8px;
  transition: background 0.2s, color 0.2s;
}
.text-button:hover { background: var(--card-soft); color: var(--text); }
.big-input {
  display: block; width: 100%; border: 0; outline: 0;
  background: transparent; color: var(--text);
  caret-color: var(--accent);
  padding: 22px 28px; min-height: 140px; resize: vertical;
  font-size: 14px; line-height: 1.65; tab-size: 4;
}
.big-input::placeholder { color: var(--muted); }

/* === Options === */
.options { padding: 8px 22px 22px; display: flex; flex-direction: column; gap: 18px; }
.option-row { display: flex; flex-direction: column; gap: 8px; }
.option-label {
  display: flex; align-items: center; gap: 10px;
  font-size: 13px; font-weight: 600; color: var(--text);
}
.opt-icon { font-size: 16px; opacity: 0.8; width: 18px; text-align: center; }
.opt-value { margin-left: auto; font-family: var(--mono); font-size: 12px; color: var(--accent); font-weight: 500; }
.opt-sub { font-size: 12px; color: var(--muted); }
.option-hint { margin: 4px 0 0; font-size: 11px; color: var(--muted); line-height: 1.5; }

/* segmented control */
.seg-control {
  display: inline-flex; flex-wrap: wrap; gap: 4px;
  background: var(--card-soft); border: 1px solid var(--line);
  border-radius: 12px; padding: 4px;
}
.seg-sm { padding: 3px; border-radius: 10px; }
.seg {
  border: 0; background: transparent; color: var(--muted);
  padding: 7px 14px; border-radius: 8px;
  font-size: 12px; font-weight: 500;
  transition: background 0.2s, color 0.2s;
}
.seg:hover { color: var(--text); }
.seg.is-active { background: var(--accent); color: #fff; box-shadow: 0 2px 6px color-mix(in srgb, var(--accent) 30%, transparent); }
.seg[disabled] { opacity: 0.4; cursor: not-allowed; }
.seg-sm .seg { padding: 5px 10px; font-size: 14px; }

/* switch */
.switch { position: relative; display: inline-block; width: 34px; height: 20px; margin-left: auto; }
.switch input { opacity: 0; width: 0; height: 0; }
.switch-track {
  position: absolute; inset: 0;
  background: var(--line); border-radius: 99px;
  transition: background 0.2s;
}
.switch-track::before {
  content: "";
  position: absolute; left: 2px; top: 2px;
  width: 16px; height: 16px; border-radius: 50%;
  background: #fff; box-shadow: 0 1px 2px rgba(0,0,0,0.15);
  transition: transform 0.2s;
}
.switch input:checked + .switch-track { background: var(--accent); }
.switch input:checked + .switch-track::before { transform: translateX(14px); }

/* color picker */
.color-row { display: flex; gap: 12px; flex-wrap: wrap; }
.color-pick {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 14px; border: 1px solid var(--line);
  border-radius: 12px; background: var(--card-soft);
  font-size: 12px; cursor: pointer;
  transition: border-color 0.2s;
}
.color-pick:hover { border-color: var(--accent); }
.color-cap { color: var(--muted); font-weight: 500; }
.color-pick input[type="color"] {
  width: 28px; height: 28px; padding: 0; border: 0;
  background: transparent; cursor: pointer;
  border-radius: 8px; overflow: hidden;
}
.color-pick input[type="color"]::-webkit-color-swatch-wrapper { padding: 0; }
.color-pick input[type="color"]::-webkit-color-swatch { border: 1px solid var(--line); border-radius: 8px; }
.color-hex {
  font-family: var(--mono); font-size: 11px; color: var(--text);
  letter-spacing: 0.02em; min-width: 64px;
}

.grad-body { display: flex; flex-direction: column; gap: 10px; padding: 8px 0 0; }
.grad-body[hidden] { display: none; }
.dir-row { display: flex; align-items: center; gap: 12px; }

/* slider */
.slider {
  -webkit-appearance: none; appearance: none;
  width: 100%; height: 6px; border-radius: 99px;
  background: var(--line); outline: none;
}
.slider::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--accent); cursor: pointer;
  border: 3px solid var(--card); box-shadow: 0 1px 4px rgba(0,0,0,0.2);
  transition: transform 0.15s;
}
.slider::-webkit-slider-thumb:hover { transform: scale(1.1); }
.slider::-moz-range-thumb {
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--accent); cursor: pointer; border: 3px solid var(--card);
}

/* === Preview panel === */
.panel-preview { padding: 26px 22px 22px; display: flex; flex-direction: column; gap: 16px; align-items: stretch; }
.preview-frame {
  display: flex; align-items: center; justify-content: center;
  padding: 24px; background: var(--card-soft);
  border: 1px dashed var(--line); border-radius: 16px;
  min-height: 320px;
}
.qr-canvas {
  width: 280px; height: 280px; max-width: 100%;
  image-rendering: pixelated; image-rendering: crisp-edges;
  background: #fff; border-radius: 8px;
  box-shadow: 0 4px 18px rgba(0,0,0,0.06);
}

.download-row { display: flex; gap: 8px; }
.dl-btn {
  flex: 1; display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  background: var(--accent); color: #fff;
  border: 0; padding: 12px 16px; border-radius: 12px;
  font-size: 14px; font-weight: 600;
  transition: transform 0.15s, box-shadow 0.2s;
}
.dl-btn:hover { transform: translateY(-1px); box-shadow: 0 4px 12px color-mix(in srgb, var(--accent) 30%, transparent); }
.dl-btn-secondary { background: var(--card-soft); color: var(--text); border: 1px solid var(--line); }
.dl-btn-secondary:hover { border-color: var(--accent); color: var(--accent); box-shadow: none; }

/* logo zone */
.logo-zone { display: flex; flex-direction: column; gap: 8px; align-items: stretch; }
.logo-drop {
  display: flex; align-items: center; justify-content: center; gap: 10px;
  padding: 18px; min-height: 90px;
  border: 1.5px dashed var(--line); border-radius: 14px;
  background: var(--card-soft); cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
}
.logo-drop:hover, .logo-drop:focus-visible {
  border-color: var(--accent); background: var(--accent-soft);
  outline: none;
}
.logo-drop.is-drag { border-color: var(--accent); background: var(--accent-soft); }
.logo-empty { display: flex; flex-direction: column; align-items: center; gap: 4px; color: var(--muted); }
.logo-icon { font-size: 22px; opacity: 0.7; }
.logo-text { font-size: 13px; font-weight: 500; color: var(--text); }
.logo-hint { font-size: 11px; color: var(--muted); }
.logo-preview {
  max-width: 100%; max-height: 80px; object-fit: contain;
  border-radius: 8px; background: #fff;
  padding: 4px;
}
.logo-zone .text-button { align-self: center; font-size: 11px; }