:root {
  color-scheme: light dark;
  --bg: #f2f4f7;
  --bg-grad-1: #f8fafc;
  --bg-grad-2: #eef2ff;
  --bg-grad-3: #f2f4f7;
  --panel: #ffffff;
  --ink: #111827;
  --muted: #4b5563;
  --accent: #0f766e;
  --warn: #b91c1c;
  --ok: #15803d;
  --line: #d1d5db;
  --panel-border: #e5e7eb;
  --btn-bg: #f8fafc;
  --btn-hover: #eef2ff;
  --field-bg: #ffffff;
  --tip-bg: rgba(15, 23, 42, 0.72);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", sans-serif;
  background: linear-gradient(145deg, var(--bg-grad-1) 0%, var(--bg-grad-2) 45%, var(--bg-grad-3) 100%);
  color: var(--ink);
}

.app {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px;
  display: grid;
  gap: 16px;
}

header h1 {
  margin: 0 0 6px;
  font-size: 1.8rem;
}

header p {
  margin: 0;
  color: var(--muted);
}

.header-links {
  margin-top: 10px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.header-links a {
  color: #0f766e;
  text-decoration: none;
  font-weight: 600;
}

.header-links a:hover {
  text-decoration: underline;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
  padding: 16px;
  box-shadow: 0 10px 25px rgba(2, 6, 23, 0.04);
}

.controls {
  display: grid;
  gap: 12px;
}

.file-upload {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: fit-content;
  padding: 10px 14px;
  background: #ecfeff;
  border: 1px solid #99f6e4;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 600;
}

.file-upload input {
  display: none;
}

.control-item {
  display: grid;
  gap: 6px;
}

input[type="range"] {
  width: 100%;
}

input[type="password"],
select {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid #cbd5e1;
  border-radius: 8px;
  font: inherit;
  background: var(--field-bg);
  color: var(--ink);
}

.actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

button {
  border: 1px solid #cbd5e1;
  background: var(--btn-bg);
  border-radius: 10px;
  padding: 8px 12px;
  font-weight: 600;
  cursor: pointer;
  color: var(--ink);
}

button:hover {
  background: var(--btn-hover);
}

.hint {
  font-size: 0.95rem;
  padding: 8px 10px;
  border-radius: 8px;
  background: #f8fafc;
  border: 1px solid var(--line);
}

.hint.ok {
  border-color: #86efac;
  background: #f0fdf4;
  color: var(--ok);
}

.hint.warn {
  border-color: #fecaca;
  background: #fef2f2;
  color: var(--warn);
}

.rule-note {
  font-size: 0.88rem;
  color: var(--muted);
  line-height: 1.4;
}

.editor-wrap {
  display: grid;
  justify-items: center;
}

.editor {
  position: relative;
  width: min(90vw, 420px);
  aspect-ratio: 413 / 531;
  border: 2px solid #cbd5e1;
  border-radius: 8px;
  overflow: hidden;
  background: var(--field-bg);
}

#canvas {
  width: 100%;
  height: 100%;
  display: block;
}

.drag-tip {
  position: absolute;
  left: 8px;
  bottom: 8px;
  background: var(--tip-bg);
  color: #fff;
  font-size: 0.75rem;
  padding: 5px 7px;
  border-radius: 6px;
}

.ad-panel h2 {
  margin: 0 0 10px;
  font-size: 1rem;
}

.legal-page {
  max-width: 860px;
}

.legal-content h2 {
  margin: 0 0 8px;
  font-size: 1.15rem;
}

.legal-content p,
.legal-content li {
  color: var(--muted);
  line-height: 1.65;
}

.legal-content ul {
  margin: 0;
  padding-left: 22px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --bg-grad-1: #0b1220;
    --bg-grad-2: #101827;
    --bg-grad-3: #111827;
    --panel: #0f172a;
    --ink: #e5e7eb;
    --muted: #94a3b8;
    --line: #334155;
    --panel-border: #334155;
    --btn-bg: #1e293b;
    --btn-hover: #334155;
    --field-bg: #0b1220;
    --tip-bg: rgba(2, 6, 23, 0.82);
  }

  .panel {
    box-shadow: 0 10px 25px rgba(2, 6, 23, 0.45);
  }

  .file-upload {
    background: #0b3a3d;
    border-color: #115e59;
    color: #d1fae5;
  }

  input[type="password"],
  select,
  button {
    border-color: #334155;
  }

  .hint {
    background: #111827;
  }
}

@media (min-width: 900px) {
  .app {
    grid-template-columns: 360px 1fr;
    align-items: start;
  }

  header {
    grid-column: 1 / -1;
  }
}