:root{
  --dark:#21313b;
  --dark2:#16242d;
  --yellow:#ffdd00;
  --red:#d98286;
  --light:#f6f7f8;
  --muted:#72808a;
  --border:#d9dfe4;
}
*{box-sizing:border-box}
body{margin:0;background:#eef2f5;color:#21313b;font-family:Arial,Helvetica,sans-serif}
a{color:inherit;text-decoration:none}
.topbar{height:auto;min-height:72px;background:var(--dark2);color:#fff;display:flex;align-items:center;justify-content:space-between;padding:16px 28px;gap:20px;box-shadow:0 8px 28px rgba(0,0,0,.18);position:sticky;top:0;z-index:9}
.brand{font-weight:900;font-size:24px;letter-spacing:1px}.brand span{color:var(--yellow);font-size:16px;margin-left:8px}
nav{display:flex;flex-wrap:wrap;gap:10px}nav a{padding:10px 14px;border-radius:12px;background:rgba(255,255,255,.08);font-weight:700;font-size:14px}nav a:hover{background:var(--yellow);color:#111}
.container{max-width:1250px;margin:26px auto;padding:0 18px}h1{margin:0 0 22px;font-size:28px}
.grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:18px}.grid.two{grid-template-columns:1fr 1fr}.grid.three{grid-template-columns:repeat(3,1fr)}
.card{background:#fff;border:1px solid var(--border);border-radius:18px;padding:22px;box-shadow:0 10px 28px rgba(20,35,50,.06)}
.stat{font-size:38px;font-weight:900}.muted{color:var(--muted)}.small{font-size:13px}.big{font-size:22px;font-weight:900}
.btn{border:none;background:var(--dark);color:#fff;padding:12px 16px;border-radius:12px;font-weight:900;cursor:pointer;display:inline-flex;align-items:center;gap:8px}.btn:hover{background:#000}.btn.yellow{background:var(--yellow);color:#111}.btn.red{background:var(--red);color:#111}.btn.gray{background:#e8edf1;color:#21313b}.btn.small{padding:8px 10px;font-size:12px}
.form-row{display:grid;grid-template-columns:1fr 1fr;gap:16px}.form-row.three{grid-template-columns:1fr 1fr 1fr}
label{display:block;font-weight:900;margin:0 0 7px}input,textarea,select{width:100%;border:1px solid #cfd8df;background:#fff;border-radius:12px;padding:12px 13px;font-size:15px}textarea{min-height:110px;resize:vertical}input:focus,textarea:focus,select:focus{outline:3px solid rgba(255,221,0,.28);border-color:#b5a000}
.actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:16px}.table{width:100%;border-collapse:separate;border-spacing:0 10px}.table th{text-align:left;color:#64727c;font-size:13px;padding:0 10px}.table td{background:#fff;padding:14px 10px;border-top:1px solid var(--border);border-bottom:1px solid var(--border)}.table td:first-child{border-left:1px solid var(--border);border-radius:12px 0 0 12px}.table td:last-child{border-right:1px solid var(--border);border-radius:0 12px 12px 0}
.alert{padding:14px 16px;border-radius:14px;margin-bottom:18px;font-weight:800}.alert.success{background:#dcfce7;color:#166534}.alert.error{background:#fee2e2;color:#991b1b}.alert.info{background:#dbeafe;color:#1e40af}
.preview-wrap{display:grid;grid-template-columns:420px 1fr;gap:20px;align-items:start}.preview-img{width:100%;border-radius:16px;box-shadow:0 12px 34px rgba(0,0,0,.16);border:1px solid #ccd5db}.thumb{width:60px;height:60px;object-fit:cover;border-radius:12px;border:1px solid #d7dde3}.code{font-family:Consolas,monospace;background:#0f1b22;color:#d6f8ff;padding:14px;border-radius:12px;overflow:auto}.pill{display:inline-flex;background:#eef2f5;border:1px solid #d5dde3;padding:5px 10px;border-radius:999px;font-weight:800;font-size:12px;color:#40515c}
.login-page{min-height:100vh;display:grid;place-items:center;background:linear-gradient(135deg,#14222b,#31424d)}.login-box{width:min(440px,92vw);background:#fff;border-radius:22px;padding:28px;box-shadow:0 20px 70px rgba(0,0,0,.35)}.login-logo{font-size:34px;font-weight:1000;color:#21313b}.login-logo span{background:var(--yellow);padding:2px 8px;margin-left:4px}
@media(max-width:900px){.grid,.grid.three,.grid.two,.form-row,.form-row.three,.preview-wrap{grid-template-columns:1fr}.topbar{align-items:flex-start;flex-direction:column}}

.alert.warning{background:#fff5d7;border-color:#e0b400;color:#6b4e00}
.alert.info{background:#eaf4ff;border-color:#8bbce8;color:#1d4c75}
.tips{line-height:1.8;margin-left:18px}
.preview-img{width:100%;max-height:520px;object-fit:contain;border:1px solid #d8dee5;border-radius:14px;background:#fff}