:root {
    --bg: #f5f7fb;
    --surface: #ffffff;
    --text: #172033;
    --muted: #6c7485;
    --primary: #2938d3;
    --border: #e5e8ef;
    --success: #16865c;
    --warning: #b7791f;
    --danger: #c0392b;
    --sidebar: #12182a;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: var(--bg);
    color: var(--text);
}

a { color: inherit; text-decoration: none; }

.layout {
    display: grid;
    grid-template-columns: 240px 1fr;
    min-height: 100vh;
}

.sidebar {
    background: var(--sidebar);
    color: white;
    padding: 24px 18px;
    display: flex;
    flex-direction: column;
}

.brand {
    display: flex;
    gap: 12px;
    align-items: center;
    margin-bottom: 32px;
}

.brand-mark {
    width: 42px;
    height: 42px;
    border-radius: 12px;
    background: white;
    color: var(--sidebar);
    display: grid;
    place-items: center;
    font-weight: 800;
}

.brand strong, .brand small { display:block; }
.brand small { opacity:.65; margin-top:3px; }

.sidebar nav { display:grid; gap:8px; }

.sidebar nav a, .sidebar-footer a {
    padding: 12px 14px;
    border-radius: 9px;
}

.sidebar nav a:hover, .sidebar-footer a:hover {
    background: rgba(255,255,255,.08);
}

.sidebar-footer { margin-top:auto; }

.main { padding: 28px; }

.topbar h1 { margin: 0 0 6px; font-size: 28px; }
.topbar p { margin: 0 0 24px; color: var(--muted); }

.cards {
    display:grid;
    grid-template-columns: repeat(4, minmax(0,1fr));
    gap:16px;
    margin-bottom:20px;
}

.card, .panel {
    background: var(--surface);
    border:1px solid var(--border);
    border-radius:14px;
    padding:20px;
}

.metric {
    font-size: 30px;
    font-weight: 700;
    margin: 8px 0 4px;
}

.label { color:var(--muted); font-size:14px; }

.grid-2 {
    display:grid;
    grid-template-columns: 1.5fr 1fr;
    gap:20px;
}

table {
    width:100%;
    border-collapse:collapse;
}

th, td {
    text-align:left;
    padding:12px 10px;
    border-bottom:1px solid var(--border);
    font-size:14px;
}

th { color:var(--muted); font-weight:600; }

.badge {
    display:inline-block;
    padding:5px 9px;
    border-radius:999px;
    background:#eef0ff;
    color:var(--primary);
    font-weight:700;
    font-size:12px;
}

.progress {
    height:9px;
    background:#eceef4;
    border-radius:999px;
    overflow:hidden;
}

.progress > span {
    display:block;
    height:100%;
    background:var(--primary);
}

.skill { margin-bottom:16px; }
.skill-head {
    display:flex;
    justify-content:space-between;
    margin-bottom:7px;
    font-size:14px;
}

.login-page {
    min-height:100vh;
    display:grid;
    place-items:center;
    padding:20px;
}

.login-box {
    width:min(420px, 100%);
    background:white;
    border:1px solid var(--border);
    border-radius:16px;
    padding:28px;
}

input, select, textarea, button {
    width:100%;
    padding:12px;
    border:1px solid #d9dde7;
    border-radius:9px;
    font:inherit;
}

.form-row { margin-bottom:14px; }
.form-row label { display:block; margin-bottom:6px; font-size:14px; }

button {
    background:var(--primary);
    color:white;
    border:0;
    cursor:pointer;
    font-weight:700;
}

.error {
    background:#fff1f0;
    color:var(--danger);
    border:1px solid #ffd6d2;
    padding:10px;
    border-radius:9px;
    margin-bottom:14px;
}

.student-head {
    display:flex;
    justify-content:space-between;
    gap:15px;
    align-items:flex-start;
    margin-bottom:20px;
}

@media (max-width: 950px) {
    .layout { grid-template-columns:1fr; }
    .sidebar { display:none; }
    .cards { grid-template-columns:repeat(2,1fr); }
    .grid-2 { grid-template-columns:1fr; }
}

@media (max-width: 560px) {
    .cards { grid-template-columns:1fr; }
    .main { padding:16px; }
}