:root {
    --primary: #1d4ed8;
    --primary-dark: #1e3a8a;
    --primary-soft: #dbeafe;
    --ink: #172033;
    --muted: #65708a;
    --surface: #ffffff;
    --background: #f4f7fb;
    --border: #dce3ee;
    --danger: #b91c1c;
    --danger-soft: #fee2e2;
    --success: #166534;
    --success-soft: #dcfce7;
    --warning: #92400e;
    --warning-soft: #fef3c7;
    --shadow: 0 12px 30px rgba(23, 32, 51, .08);
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
* { box-sizing: border-box; }
html { background: var(--background); color: var(--ink); }
body { margin: 0; min-height: 100vh; background: radial-gradient(circle at top right, #e9f2ff 0, transparent 28rem), var(--background); }
a { color: var(--primary); text-decoration: none; }
button, input, select, textarea { font: inherit; }
.topbar {
    position: sticky; top: 0; z-index: 20;
    min-height: 64px; display: flex; align-items: center; gap: 24px;
    padding: 10px max(18px, calc((100vw - 1160px) / 2));
    background: rgba(255,255,255,.94); border-bottom: 1px solid var(--border); backdrop-filter: blur(12px);
}
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 800; white-space: nowrap; }
.brand-mark { display: grid; place-items: center; width: 38px; height: 38px; border-radius: 12px; background: linear-gradient(135deg, var(--primary), #2563eb); color: white; box-shadow: 0 8px 18px rgba(29,78,216,.22); }
.main-nav { margin-left: auto; display: flex; align-items: center; gap: 5px; }
.main-nav a { padding: 9px 11px; border-radius: 10px; color: #34405a; font-weight: 650; font-size: .94rem; }
.main-nav a:hover { background: var(--primary-soft); color: var(--primary-dark); }
.nav-user { margin-left: 8px; padding-left: 12px; border-left: 1px solid var(--border); color: var(--muted); font-size: .86rem; }
.main-nav .logout-link { color: var(--danger); }
.nav-toggle { display: none; margin-left: auto; border: 0; background: var(--primary-soft); color: var(--primary-dark); border-radius: 10px; width: 42px; height: 42px; font-size: 1.3rem; }
.container { width: min(1160px, calc(100% - 28px)); margin: 26px auto 60px; }
.footer { color: var(--muted); text-align: center; padding: 22px; font-size: .85rem; }
.hero { display: grid; grid-template-columns: 1.35fr .65fr; gap: 22px; align-items: stretch; margin-bottom: 24px; }
.hero-panel, .card { background: rgba(255,255,255,.96); border: 1px solid var(--border); border-radius: 20px; box-shadow: var(--shadow); }
.hero-panel { padding: 30px; }
.hero-panel h1 { margin: 0 0 10px; font-size: clamp(1.8rem, 4vw, 2.8rem); line-height: 1.08; }
.hero-panel p { color: var(--muted); line-height: 1.7; margin: 0; }
.hero-accent { display: grid; place-items: center; min-height: 180px; background: linear-gradient(145deg, var(--primary-dark), var(--primary)); color: white; overflow: hidden; position: relative; }
.hero-accent::before, .hero-accent::after { content: ''; position: absolute; border-radius: 50%; background: rgba(255,255,255,.11); }
.hero-accent::before { width: 190px; height: 190px; top: -80px; right: -50px; }
.hero-accent::after { width: 100px; height: 100px; bottom: -35px; left: -20px; }
.hero-number { font-size: 3rem; font-weight: 900; z-index: 1; }
.hero-label { z-index: 1; opacity: .85; }
.page-head { display: flex; align-items: end; justify-content: space-between; gap: 18px; margin-bottom: 20px; }
.page-head h1 { margin: 0; font-size: clamp(1.7rem, 3vw, 2.35rem); }
.page-head p { margin: 6px 0 0; color: var(--muted); }
.grid { display: grid; gap: 18px; }
.grid-2 { grid-template-columns: repeat(2, minmax(0,1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0,1fr)); }
.grid-4 { grid-template-columns: repeat(4, minmax(0,1fr)); }
.card { padding: 22px; }
.card h2, .card h3 { margin-top: 0; }
.stat-card { position: relative; overflow: hidden; }
.stat-value { font-size: 2.25rem; line-height: 1; font-weight: 900; color: var(--primary-dark); }
.stat-label { margin-top: 8px; color: var(--muted); }
.stat-icon { position: absolute; right: 16px; top: 14px; font-size: 2.2rem; opacity: .16; }
.actions { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 7px; min-height: 42px; padding: 9px 15px; border: 0; border-radius: 11px; font-weight: 750; cursor: pointer; transition: transform .12s ease, filter .12s ease; }
.btn:hover { filter: brightness(.98); transform: translateY(-1px); }
.btn-primary { background: var(--primary); color: white; }
.btn-secondary { background: #e9eef7; color: #263552; }
.btn-success { background: #15803d; color: white; }
.btn-danger { background: var(--danger-soft); color: var(--danger); }
.btn-warning { background: var(--warning-soft); color: var(--warning); }
.btn-sm { min-height: 34px; padding: 6px 10px; font-size: .86rem; border-radius: 9px; }
.form-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 15px; }
.form-group { display: flex; flex-direction: column; gap: 7px; }
.form-group.full { grid-column: 1 / -1; }
label { font-weight: 700; font-size: .92rem; }
.input, select, textarea { width: 100%; border: 1px solid #cbd5e1; border-radius: 11px; padding: 11px 12px; color: var(--ink); background: #fff; outline: none; }
.input:focus, select:focus, textarea:focus { border-color: #60a5fa; box-shadow: 0 0 0 4px rgba(96,165,250,.18); }
.help { color: var(--muted); font-size: .84rem; line-height: 1.5; }
.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: 14px; }
table { width: 100%; border-collapse: collapse; background: white; }
th, td { padding: 12px 13px; border-bottom: 1px solid #e7ecf3; text-align: left; vertical-align: middle; }
th { background: #f8fafc; color: #44506a; font-size: .82rem; text-transform: uppercase; letter-spacing: .035em; }
tr:last-child td { border-bottom: 0; }
.badge { display: inline-flex; align-items: center; padding: 5px 9px; border-radius: 999px; font-size: .78rem; font-weight: 800; }
.badge-admin { background: #ede9fe; color: #6d28d9; }
.badge-teacher { background: #dbeafe; color: #1d4ed8; }
.badge-student { background: #dcfce7; color: #166534; }
.badge-active { background: var(--success-soft); color: var(--success); }
.badge-inactive { background: var(--danger-soft); color: var(--danger); }
.alert { padding: 13px 15px; border-radius: 12px; margin-bottom: 16px; border: 1px solid transparent; }
.alert-success { background: var(--success-soft); color: var(--success); border-color: #bbf7d0; }
.alert-error { background: var(--danger-soft); color: var(--danger); border-color: #fecaca; }
.alert-warning { background: var(--warning-soft); color: var(--warning); border-color: #fde68a; }
.empty { padding: 34px 18px; text-align: center; color: var(--muted); }
.login-shell { min-height: calc(100vh - 170px); display: grid; place-items: center; }
.login-card { width: min(440px, 100%); padding: 30px; }
.login-card h1 { margin: 0 0 8px; }
.login-card > p { color: var(--muted); margin: 0 0 22px; }
.score-picker { display: grid; grid-template-columns: repeat(4, 1fr); gap: 9px; }
.score-option { position: relative; }
.score-option input { position: absolute; opacity: 0; pointer-events: none; }
.score-option label { display: grid; place-items: center; min-height: 60px; border: 2px solid var(--border); border-radius: 14px; background: white; cursor: pointer; font-size: 1.2rem; font-weight: 900; }
.score-option input:checked + label { border-color: var(--primary); background: var(--primary-soft); color: var(--primary-dark); box-shadow: 0 0 0 3px rgba(37,99,235,.12); }
.scanner-layout { display: grid; grid-template-columns: minmax(0,1.1fr) minmax(280px,.9fr); gap: 18px; }
#reader { overflow: hidden; border-radius: 16px; }
#reader video { border-radius: 12px; }
.scan-result { min-height: 94px; display: grid; place-items: center; text-align: center; border: 2px dashed var(--border); border-radius: 14px; padding: 14px; color: var(--muted); }
.scan-result.success { border-color: #86efac; background: #f0fdf4; color: #166534; }
.scan-result.error { border-color: #fca5a5; background: #fef2f2; color: #991b1b; }
.qr-card { text-align: center; }
#qrcode { display: inline-block; padding: 18px; background: white; border: 1px solid var(--border); border-radius: 18px; }
.student-meta { margin-top: 16px; display: grid; gap: 5px; color: var(--muted); }
.score-pill { display: inline-grid; place-items: center; min-width: 46px; height: 34px; padding: 0 10px; border-radius: 999px; font-weight: 900; }
.score-excellent { background: #dcfce7; color: #166534; }
.score-good { background: #dbeafe; color: #1d4ed8; }
.score-needs-work { background: #fef3c7; color: #92400e; }
.toolbar { display: flex; gap: 10px; flex-wrap: wrap; align-items: end; margin-bottom: 15px; }
.toolbar .form-group { min-width: 190px; flex: 1; }
.notice { padding: 14px; border-left: 4px solid var(--primary); background: #eff6ff; border-radius: 8px 12px 12px 8px; color: #27416e; line-height: 1.55; }
.kbd { padding: 2px 6px; border-radius: 6px; border: 1px solid #cbd5e1; background: #f8fafc; font-family: ui-monospace, monospace; font-size: .85em; }

.check-row { display: flex; align-items: flex-start; gap: 9px; cursor: pointer; font-weight: 700; }
.check-row input { width: 18px; height: 18px; margin: 2px 0 0; accent-color: var(--primary); }
details summary { cursor: pointer; color: var(--primary-dark); }
@media (max-width: 920px) {
    .grid-4 { grid-template-columns: repeat(2, minmax(0,1fr)); }
    .grid-3 { grid-template-columns: repeat(2, minmax(0,1fr)); }
    .scanner-layout, .hero { grid-template-columns: 1fr; }
    .nav-toggle { display: inline-grid; place-items: center; }
    .main-nav { display: none; position: absolute; top: 64px; left: 14px; right: 14px; padding: 10px; border: 1px solid var(--border); border-radius: 14px; background: white; box-shadow: var(--shadow); flex-direction: column; align-items: stretch; }
    .nav-open .main-nav { display: flex; }
    .main-nav a { padding: 11px 12px; }
    .nav-user { margin: 4px 0 0; padding: 10px 12px; border-left: 0; border-top: 1px solid var(--border); }
}
@media (max-width: 640px) {
    .container { width: min(100% - 20px, 1160px); margin-top: 18px; }
    .card, .hero-panel { padding: 17px; border-radius: 16px; }
    .grid-2, .grid-3, .grid-4, .form-grid { grid-template-columns: 1fr; }
    .form-group.full { grid-column: auto; }
    .page-head { align-items: stretch; flex-direction: column; }
    .page-head .actions .btn { flex: 1; }
    .score-picker { grid-template-columns: repeat(2, 1fr); }
    th, td { padding: 10px; }
}
@media print {
    .topbar, .footer, .no-print, .alert { display: none !important; }
    body { background: white; }
    .container { margin: 0 auto; }
    .card { box-shadow: none; border: 0; }
    .qr-card { padding-top: 20mm; }
}