*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}:root{--bg: #ffffff;--surface: #f5f5f5;--surface2: #ebebeb;--border: #d0d0d0;--accent: #2563eb;--accent-hover: #1d4ed8;--text: #111111;--text-muted: #666666;--success: #16a34a;--success-tint: #dcfce7;--error: #dc2626;--error-tint: #fee2e2;--radius: 8px;--radius-sm: 4px}body{background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;font-size:14px;line-height:1.5;min-height:100vh}.app{max-width:640px;margin:0 auto;padding:48px 24px 80px}.back-link{display:inline-block;color:var(--text-muted);text-decoration:none;font-size:13px;font-weight:600;margin-bottom:24px}.back-link:hover{color:var(--accent)}.header{text-align:center;margin-bottom:32px}.header h1{font-size:2rem;font-weight:700;letter-spacing:-.02em}.subtitle{color:var(--text-muted);margin-top:8px}.panel{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:24px;margin-bottom:24px}.panel__title{font-size:13px;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--text-muted);margin-bottom:18px}.control-label{font-size:12px;font-weight:600;color:var(--text-muted);text-transform:uppercase;letter-spacing:.05em}.field{display:flex;flex-direction:column;gap:6px;flex:1}.text-input{background:var(--surface2);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text);font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:13px;padding:9px 12px;outline:none;transition:border-color .15s;width:100%}.text-input:focus{border-color:var(--accent)}.converter{display:flex;gap:20px;align-items:flex-start}.swatch{display:block;width:72px;height:72px;flex-shrink:0;border-radius:var(--radius);border:1px solid var(--border);cursor:pointer;overflow:hidden}.swatch--sm{width:44px;height:44px}.swatch input[type=color]{opacity:0;width:100%;height:100%;cursor:pointer}.fields{flex:1;display:flex;flex-direction:column;gap:12px}.error{color:var(--error);font-size:13px;margin-top:12px}.contrast{display:flex;gap:20px}.contrast__color{flex:1;display:flex;gap:12px;align-items:flex-end}.contrast__preview{margin-top:20px;border-radius:var(--radius);border:1px solid var(--border);padding:32px;display:flex;align-items:center;justify-content:center;font-size:2.5rem;font-weight:700;transition:background .15s,color .15s}.contrast__result{display:flex;align-items:baseline;justify-content:center;gap:4px;margin-top:16px}.contrast__ratio{font-size:1.75rem;font-weight:700}.contrast__ratio-label{color:var(--text-muted);font-size:1rem}.badges{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin-top:16px}.badge{font-size:12px;font-weight:700;padding:4px 10px;border-radius:20px;background:var(--surface2);color:var(--text-muted)}.badge--pass{background:var(--success-tint);color:var(--success)}.badge--fail{background:var(--error-tint);color:var(--error)}@media(max-width:480px){.contrast{flex-direction:column}}