/* ══════════════════════════════════════════
   在线白板涂鸦 - 自定义样式
   ══════════════════════════════════════════ */
:root {
  --bg: #FAFAF9; --bg-alt: #F5F5F4; --surface: #FFFFFF; --border: #E7E5E4; --border-strong: #D6D3D1;
  --text: #1E293B; --text-secondary: #52525B; --text-muted: #71717A;
  --primary: #4F46E5; --primary-hover: #4338CA; --primary-light: rgba(79,70,229,0.08);
  --secondary: #F97316; --accent: #EC4899; --success: #059669;
  --radius: 10px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04); --shadow: 0 4px 12px rgba(0,0,0,0.06);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { font-family:'Inter','Noto Sans SC',system-ui,sans-serif; background:var(--bg); color:var(--text); line-height:1.6; min-height:100vh; -webkit-font-smoothing:antialiased; }
.toast { position:fixed; top:24px; right:24px; background:var(--text); color:var(--bg); padding:10px 18px; border-radius:100px; font-size:14px; font-weight:500; display:flex; align-items:center; gap:8px; z-index:1000; transform:translateX(calc(100% + 40px)); transition:transform 0.3s cubic-bezier(0.34,1.56,0.64,1); box-shadow:0 4px 16px rgba(0,0,0,0.12); }
.toast.show { transform:translateX(0); }
.toast-dot { width:8px; height:8px; background:var(--success); border-radius:50%; }
.page { max-width:960px; margin:0 auto; padding:0 32px; }
::-webkit-scrollbar{width:8px}::-webkit-scrollbar-track{background:#f1f5f9}::-webkit-scrollbar-thumb{background:#A5B4FC;border-radius:4px}::-webkit-scrollbar-thumb:hover{background:#4F46E5}
::selection { background:rgba(79,70,229,0.2); color:#1E293B; }

.draw-toolbar { margin:16px 0; background:var(--surface); border:1px solid var(--border); border-radius:var(--radius); padding:12px 16px; box-shadow:var(--shadow-sm); display:flex; flex-wrap:wrap; gap:12px; align-items:center; }
.tool-group { display:flex; align-items:center; gap:8px; }
.tool-label { font-size:11px; font-weight:600; text-transform:uppercase; letter-spacing:0.05em; color:var(--text-muted); }
.color-pick { width:32px; height:32px; border:none; border-radius:6px; cursor:pointer; padding:0; background:transparent; }
.tool-range { width:80px; accent-color:var(--primary); }
.size-label { font-family:'SF Mono','Cascadia Code','Fira Code',monospace; font-size:12px; color:var(--text-muted); min-width:30px; }
.tool-select { padding:6px 10px; font-family:inherit; font-size:13px; background:var(--bg-alt); border:1px solid var(--border); border-radius:6px; color:var(--text); outline:none; cursor:pointer; }
.tool-btn { padding:8px 16px; font-family:inherit; font-size:13px; font-weight:500; background:transparent; border:1px solid var(--border); border-radius:100px; color:var(--text-secondary); cursor:pointer; transition:all 0.15s ease; white-space:nowrap; }
.tool-btn:hover { border-color:var(--primary); color:var(--primary); background:var(--primary-light); }
.tool-btn.active { background:#fef2f2; border-color:#fca5a5; color:#dc2626; }
.tool-btn--primary { background:var(--primary); color:white; border-color:var(--primary); }
.tool-btn--primary:hover { background:var(--primary-hover); color:white; }

.draw-wrap { width:100%; background:var(--surface); border:1px solid var(--border); border-radius:var(--radius); overflow:hidden; margin-bottom:32px; box-shadow:var(--shadow); touch-action:none; }
.draw-wrap canvas { display:block; width:100%; height:auto; cursor:crosshair; }

.guide-section { margin-top:16px; margin-bottom:64px; background:#ffffff; border:1px solid var(--border); border-radius:12px; overflow:hidden; }
.guide-toggle { display:flex; align-items:center; justify-content:space-between; width:100%; padding:14px 20px; background:none; border:none; cursor:pointer; transition:background 0.15s ease; }
.guide-toggle:hover { background:var(--bg-alt); }
.guide-toggle-title { display:flex; align-items:center; gap:8px; font-size:14px; font-weight:600; color:#1E293B; }
.guide-toggle.open .toggle-arrow { transform:rotate(180deg); }
.toggle-arrow { transition:transform 0.2s ease; color:var(--text-muted); }
.guide-list { padding:0 20px 20px; }
.guide-list.hidden { display:none; }
.guide-item { padding:16px 0; border-top:1px solid var(--border); }
.guide-item:first-child { border-top:1px solid var(--border); }
.guide-item-title { font-size:14px; font-weight:600; color:#1E293B; margin-bottom:6px; }
.guide-item-body { font-size:13px; color:var(--text-secondary); line-height:1.8; }

@media (max-width:768px) {
  .page { padding:0 16px; }
  .draw-toolbar { gap:8px; }
}