:root{--bg:#f4f5f7;--card:#fff;--fg:#1b1d21;--mut:#6b7280;--line:#e3e5e9;--acc:#2563eb;--bad:#dc2626}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){--bg:#0f1115;--card:#181b21;--fg:#e8eaed;--mut:#9aa1ac;--line:#2a2e36;--acc:#5b8cff;--bad:#f87171}}
:root[data-theme="dark"]{--bg:#0f1115;--card:#181b21;--fg:#e8eaed;--mut:#9aa1ac;--line:#2a2e36;--acc:#5b8cff;--bad:#f87171}
*{box-sizing:border-box}html,body{margin:0}body{background:var(--bg);color:var(--fg);font:16px/1.45 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;min-height:100vh;display:flex;align-items:center;justify-content:center;padding:24px 16px}
main{width:100%;max-width:560px}h1{font-size:24px;margin:0 0 4px}.sub{color:var(--mut);font-size:14px}
.card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:20px;margin-top:16px}
button,.btn{display:block;width:100%;border:0;border-radius:12px;padding:14px;font:600 16px inherit;font-family:inherit;background:var(--acc);color:#fff;cursor:pointer;text-align:center;text-decoration:none}
button.sec{background:transparent;color:var(--acc);border:1px solid var(--line)}
input{width:100%;padding:12px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--fg);font:16px inherit;font-family:inherit;margin:6px 0 12px}
label{font-size:14px;color:var(--mut)}.err{color:var(--bad);font-size:14px;min-height:20px;margin-top:10px}
a{color:var(--acc)}