:root{color-scheme:light dark;--bg: #ffffff;--bg-elevated: #f6f6f8;--text: #1a1a1e;--text-muted: #6b6b73;--accent: #2f6fed;--border: #e3e3e8;--error: #c62828;--radius: 10px}@media(prefers-color-scheme:dark){:root{--bg: #0b0b0f;--bg-elevated: #14141a;--text: #ececf1;--text-muted: #9a9aa5;--accent: #6d9bff;--border: #26262e;--error: #ff7b7b}}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Noto Sans TC,sans-serif;background:var(--bg);color:var(--text);line-height:1.5}.page-center{min-height:100vh;display:grid;place-items:center;padding:1rem}.login-card{width:100%;max-width:360px;background:var(--bg-elevated);border:1px solid var(--border);border-radius:var(--radius);padding:1.5rem;display:flex;flex-direction:column;gap:.5rem}.brand{margin:0;font-size:1.5rem;letter-spacing:.02em}.muted{color:var(--text-muted)}label{margin-top:.5rem;font-size:.875rem;color:var(--text-muted)}input{padding:.6rem .75rem;border:1px solid var(--border);border-radius:8px;background:var(--bg);color:var(--text);font:inherit}button{margin-top:.75rem;padding:.6rem 1rem;border:0;border-radius:8px;background:var(--accent);color:#fff;font:inherit;font-weight:600;cursor:pointer}button:disabled{opacity:.6;cursor:default}.error{color:var(--error);font-size:.875rem;margin:.25rem 0 0}.shell{min-height:100vh;display:flex;flex-direction:column}.topbar{display:flex;align-items:center;gap:1rem;padding:.75rem 1.25rem;border-bottom:1px solid var(--border);background:var(--bg-elevated)}.topbar .brand{font-size:1.125rem;margin-right:auto}.content{padding:1.5rem 1.25rem;max-width:960px;width:100%}