:root{--bg:#fff;--side:#f7f7f8;--ink:#2d333a;--muted:#8e8ea0;--line:#e6e6ea;--acc:#4f46e5;}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,Segoe UI,Roboto,Helvetica,sans-serif;color:var(--ink);background:var(--bg)}

/* login */
.login-bg{display:flex;align-items:center;justify-content:center;min-height:100vh;background:#f7f7f8}
.login-card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:34px;width:380px;box-shadow:0 4px 24px rgba(0,0,0,.05)}
.login-card h1{margin:0 0 4px;font-size:21px}.login-card .sub{color:var(--muted);font-size:13px;margin:0 0 22px}
.login-card label{display:block;font-size:13px;font-weight:600;margin-top:12px}
.login-card input{width:100%;border:1px solid var(--line);border-radius:9px;padding:11px;margin-top:5px;font-size:14px;outline:none}
.login-card input:focus{border-color:var(--acc)}
.login-card button{margin-top:20px;width:100%;background:var(--acc);color:#fff;border:0;border-radius:10px;padding:12px;font-weight:600;cursor:pointer}
.login-card .hint{font-size:11px;color:var(--muted);margin-top:16px;text-align:center}
.error{background:#fdecec;color:#d33;border:1px solid #f5c2c2;padding:9px;border-radius:8px;font-size:13px;margin-bottom:8px}

/* admin */
header{display:flex;justify-content:space-between;align-items:center;padding:14px 22px;background:#fff;border-bottom:1px solid var(--line)}
header .brand{font-weight:700}header .who{display:flex;gap:16px;font-size:13px;color:var(--muted);align-items:center}
header .who a{color:var(--acc);text-decoration:none}
main{max-width:1000px;margin:22px auto;padding:0 18px}
.panel{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px 20px;margin-bottom:18px}
.panel h2{font-size:14px;color:var(--muted);margin:0 0 14px}
.tbl{width:100%;border-collapse:collapse;font-size:13px}
.tbl th,.tbl td{text-align:left;padding:7px 9px;border-bottom:1px solid var(--line)}
.tbl th{color:var(--muted)}
.userform{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:14px}
.userform input,.userform select{border:1px solid var(--line);border-radius:8px;padding:9px;flex:1;min-width:140px}
.userform button{background:var(--acc);color:#fff;border:0;border-radius:8px;padding:9px 16px;cursor:pointer}
.a-login{color:var(--acc)}.a-ask{color:#2b6cb0}.a-logout{color:var(--muted)}.a-add_user{color:#b7791f}
.muted{color:var(--muted)}