/* ============================================================
   Online Exam System - Stylesheet
   ============================================================ */
:root {
    --primary: #4e7cff;
    --primary-dark: #3a63d8;
    --secondary: #6c757d;
    --success: #00b894;
    --danger: #e74c3c;
    --warning: #fd9644;
    --info: #0984e3;
    --bg: #f0f2f8;
    --card: #ffffff;
    --text: #2d3436;
    --text-light: #7b8590;
    --border: #e3e7ef;
    --radius: 12px;
    --shadow: 0 2px 10px rgba(30, 40, 90, .06);
    --grad: linear-gradient(135deg, #4e7cff, #6a5bff);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { min-height: 100%; }
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg);
    color: var(--text);
    font-size: 14px;
    line-height: 1.5;
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- Auth pages ---------- */
.auth-body {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: var(--grad);
    padding: 20px;
}
.auth-box {
    background: #fff;
    width: 100%;
    max-width: 400px;
    padding: 35px 40px;
    border-radius: 18px;
    box-shadow: 0 15px 50px rgba(0, 0, 0, .25);
}
.auth-box h1 { font-size: 22px; margin: 6px 0 18px; color: var(--primary-dark); }
.auth-logo {
    font-size: 20px;
    font-weight: 800;
    letter-spacing: .3px;
    margin-bottom: 6px;
    color: var(--primary);
}
.auth-hint { margin-top: 14px; color: var(--text-light); font-size: 12px; text-align: center; }
.auth-link { margin-top: 12px; text-align: center; font-size: 13px; }
.hero-box { text-align: center; max-width: 500px; }
.hero-text { color: var(--text-light); margin: 8px 0 22px; }
.hero-buttons { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

/* ---------- Layout ---------- */
.topbar {
    background: var(--grad);
    color: #fff;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 12px rgba(30, 40, 90, .18);
}
.topbar-inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 20px;
    height: 58px;
    display: flex;
    align-items: center;
    gap: 24px;
}
.brand { font-weight: 800; font-size: 18px; color: #fff; white-space: nowrap; }
.brand:hover { text-decoration: none; }
.brand span { font-weight: 400; opacity: .85; font-size: 13px; }
.topnav { display: flex; gap: 4px; flex: 1; overflow-x: auto; }
.topnav a {
    color: rgba(255, 255, 255, .85);
    padding: 8px 13px;
    border-radius: 8px;
    font-weight: 600;
    white-space: nowrap;
}
.topnav a:hover { background: rgba(255, 255, 255, .12); text-decoration: none; color: #fff; }
.topnav a.active { background: #fff; color: var(--primary-dark); }
.topbar-right { display: flex; align-items: center; gap: 12px; }
.user-chip {
    background: rgba(255, 255, 255, .18);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    white-space: nowrap;
}
.container { max-width: 1280px; margin: 0 auto; padding: 24px 20px 60px; }

/* ---------- Page head ---------- */
.page-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 20px;
}
.page-head h2 { font-size: 22px; color: var(--text); }

/* ---------- Cards ---------- */
.card {
    background: var(--card);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
    margin-bottom: 22px;
}
.card-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 16px;
}
.card-head h3 { font-size: 16px; color: var(--primary-dark); }
.card h3 { font-size: 16px; color: var(--primary-dark); margin-bottom: 12px; }
.sub-text { font-size: 12px; color: var(--text-light); font-weight: 400; }

/* ---------- Grid ---------- */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 16px; margin-bottom: 24px; }
.stat-card {
    background: var(--card);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
    border-left: 5px solid var(--c, var(--primary));
    text-align: center;
}
.stat-num { font-size: 28px; font-weight: 800; color: var(--c, var(--primary)); }
.stat-label { font-size: 13px; color: var(--text-light); margin-top: 2px; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; align-items: start; }
@media (max-width: 960px) { .two-col { grid-template-columns: 1fr; } }

/* ---------- Forms ---------- */
.form-group { margin-bottom: 14px; }
.form-group label { display: block; font-weight: 600; font-size: 13px; margin-bottom: 6px; }
.form-control {
    width: 100%;
    padding: 10px 12px;
    border: 1.5px solid var(--border);
    border-radius: 9px;
    font-size: 14px;
    background: #fafbfe;
    color: var(--text);
    transition: border-color .15s;
}
.form-control:focus { outline: none; border-color: var(--primary); background: #fff; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 600px) { .form-row { grid-template-columns: 1fr; } }
.btn-row { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.inline-form { display: inline-flex; }
.filter-bar { padding: 16px; }
.filter-form { display: flex; gap: 14px; align-items: flex-end; flex-wrap: wrap; }
.filter-form .form-group { margin-bottom: 0; flex: 1; min-width: 160px; }

/* ---------- Buttons ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 10px 18px;
    border: none;
    border-radius: 9px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all .15s;
    background: var(--primary);
    color: #fff;
}
.btn:hover { filter: brightness(1.08); text-decoration: none; }
.btn:disabled { opacity: .5; cursor: not-allowed; filter: none; }
.btn-block { width: 100%; }
.btn-lg { padding: 13px 26px; font-size: 16px; }
.btn-sm { padding: 6px 12px; font-size: 12px; border-radius: 7px; }
.btn-primary { background: var(--primary); }
.btn-secondary { background: var(--secondary); }
.btn-success { background: var(--success); }
.btn-danger { background: var(--danger); }
.btn-warning { background: var(--warning); color: #fff; }

/* ---------- Tables ---------- */
.table-wrap { overflow-x: auto; }
.table { width: 100%; border-collapse: collapse; }
.table th {
    text-align: left;
    padding: 10px 12px;
    background: #f6f7fc;
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: .4px;
    color: var(--text-light);
    border-bottom: 2px solid var(--border);
    white-space: nowrap;
}
.table td {
    padding: 10px 12px;
    border-bottom: 1px solid var(--border);
    vertical-align: top;
}
.table tr:last-child td { border-bottom: none; }
.table tr:hover td { background: #fafbff; }
.small-cell { font-size: 12.5px; }
.empty { text-align: center; color: var(--text-light); padding: 26px !important; }
.actions-cell .btn, .actions-cell form { margin: 2px 0; }

/* ---------- Badges ---------- */
.badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 11.5px;
    font-weight: 700;
    color: #fff;
}
.badge-success { background: var(--success); }
.badge-danger { background: var(--danger); }
.badge-warning { background: var(--warning); }
.badge-info { background: var(--info); }
.badge-score { background: var(--primary); }
.badge-answer { background: #6c5ce7; }

/* ---------- Alerts ---------- */
.alert {
    padding: 12px 16px;
    border-radius: 10px;
    margin-bottom: 16px;
    font-size: 14px;
}
.alert-success { background: #e3fbf2; color: #087f5b; border: 1px solid #b2f2dd; }
.alert-danger { background: #fdecea; color: #a93226; border: 1px solid #f5c6cb; }
.alert-info { background: #e7f1ff; color: #1b6ec2; border: 1px solid #c4dcff; }

/* ---------- Questions page ---------- */
.question-block {
    border: 1.5px dashed var(--border);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 16px;
    background: #fafbfe;
}
.question-block-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    color: var(--primary-dark);
}
.options-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 640px) { .options-grid { grid-template-columns: 1fr; } }

/* ---------- Students ---------- */
.stu-photo {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    object-fit: cover;
    display: block;
    margin-bottom: 6px;
}
.no-photo {
    background: #eef0f6;
    color: var(--text-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 700;
}
.profile-photo {
    width: 130px;
    height: 130px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 14px;
    border: 4px solid var(--primary);
}
.placeholder-photo {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 48px;
    font-weight: 800;
    color: #fff;
    background: var(--grad);
}
.photo-form { display: flex; flex-direction: column; gap: 10px; margin-bottom: 16px; }
.profile-table { margin-top: 8px; }
.profile-table th { width: 130px; }
.profile-table td, .profile-table th { border-bottom: 1px solid var(--border); padding: 9px 10px; text-align: left; font-size: 13.5px; }

/* ---------- Modal ---------- */
.modal {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(10, 15, 40, .55);
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
}
.modal-box {
    background: #fff;
    border-radius: 16px;
    padding: 26px;
    width: 100%;
    max-width: 460px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, .3);
}
.modal-lg { max-width: 640px; }
.modal-box h3 { margin-bottom: 16px; color: var(--primary-dark); }

/* ============================================================
   EXAM PAGE
   ============================================================ */
.exam-body { background: var(--bg); min-height: 100vh; }
.exam-topbar {
    background: var(--grad);
    color: #fff;
    padding: 10px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    flex-wrap: wrap;
    position: sticky;
    top: 0;
    z-index: 200;
    box-shadow: 0 3px 14px rgba(30, 40, 90, .25);
}
.exam-title { display: flex; flex-direction: column; }
.exam-title strong { font-size: 17px; }
.exam-title .sub-text { color: rgba(255, 255, 255, .8); }
.timer-box { text-align: center; }
.timer-label { font-size: 11px; text-transform: uppercase; letter-spacing: 1px; opacity: .8; }
.timer {
    font-size: 26px;
    font-weight: 800;
    font-variant-numeric: tabular-nums;
    background: rgba(255, 255, 255, .15);
    padding: 3px 16px;
    border-radius: 10px;
    min-width: 120px;
}
.timer-danger { background: var(--danger) !important; animation: blink 1s infinite; }
@keyframes blink { 50% { opacity: .55; } }

.exam-main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 20px;
    align-items: start;
}
@media (max-width: 860px) {
    .exam-main { grid-template-columns: 1fr; }
    .exam-palette { order: -1; }
}

/* Question area */
.question-card { min-height: 380px; }
.question-no {
    font-size: 14px;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 14px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border);
}
.question-text { font-size: 17px; font-weight: 600; margin-bottom: 20px; white-space: pre-wrap; }
.option-list { display: flex; flex-direction: column; gap: 12px; }
.option-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    border: 2px solid var(--border);
    border-radius: 11px;
    padding: 13px 15px;
    cursor: pointer;
    transition: all .15s;
    background: #fff;
}
.option-item:hover { border-color: var(--primary); background: #f4f7ff; }
.option-item.selected { border-color: var(--primary); background: #eef3ff; }
.option-item input[type="radio"] { margin-top: 3px; accent-color: var(--primary); }
.option-key {
    background: var(--primary);
    color: #fff;
    font-weight: 800;
    width: 26px;
    height: 26px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    flex-shrink: 0;
}
.option-text { flex: 1; }
.nav-row {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    margin-top: 6px;
}
.nav-row .btn { min-width: 140px; }

/* Palette */
.palette-title { margin-bottom: 12px; }
.palette-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(44px, 1fr));
    gap: 8px;
    margin-bottom: 14px;
}
.palette-box {
    height: 42px;
    border: 2px solid var(--border);
    border-radius: 9px;
    font-weight: 700;
    cursor: pointer;
    color: var(--text);
    background: #fff;
    transition: all .12s;
}
.palette-box:hover { transform: scale(1.07); }
.box-white { background: #fff; color: var(--text); }
.box-orange { background: var(--warning); color: #fff; border-color: var(--warning); }
.box-green { background: var(--success); color: #fff; border-color: var(--success); }
.box-current { outline: 3px solid var(--primary); outline-offset: 1px; }
.palette-legend { display: flex; flex-direction: column; gap: 7px; margin-bottom: 14px; font-size: 12.5px; }
.palette-legend div { display: flex; align-items: center; gap: 9px; }
.dot { width: 15px; height: 15px; border-radius: 4px; display: inline-block; border: 2px solid var(--border); }
.dot-white { background: #fff; }
.dot-orange { background: var(--warning); border-color: var(--warning); }
.dot-green { background: var(--success); border-color: var(--success); }
.palette-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    margin-bottom: 16px;
}
.stat {
    background: #f6f7fc;
    border-radius: 10px;
    padding: 10px;
    text-align: center;
}
.stat .stat-num { font-size: 20px; font-weight: 800; color: var(--text); }
.stat .stat-label { font-size: 11px; color: var(--text-light); }
.green-num { color: var(--success) !important; }
.orange-num { color: var(--warning) !important; }

/* ---------- Exam sets ---------- */
.sets-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 18px;
}
.set-card-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border);
}
.set-badge {
    background: var(--grad);
    color: #fff;
    font-weight: 800;
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
}
.set-questions {
    padding-left: 20px;
    font-size: 13px;
    display: flex;
    flex-direction: column;
    gap: 6px;
}
.set-questions li { color: var(--text); }

/* ---------- Result pages ---------- */
.result-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 16px;
    margin-bottom: 18px;
}
.result-box {
    background: var(--card);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
    text-align: center;
}
.result-num { font-size: 30px; font-weight: 800; color: var(--primary); }
.result-label { font-size: 13px; color: var(--text-light); }
.green-text { color: var(--success); }
.red-text { color: var(--danger); }

.review-question {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 14px;
    background: #fafbfe;
}
.review-head {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 10px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}
.review-head strong { font-size: 15px; }
.review-options { margin-top: 10px; }
.review-option {
    border: 2px solid var(--border);
    border-radius: 9px;
    padding: 9px 12px;
    font-size: 13px;
    position: relative;
}
.opt-correct { border-color: var(--success); background: #e3fbf2; }
.opt-wrong { border-color: var(--danger); background: #fdecea; }
.tick { color: var(--success); font-weight: 800; float: right; }
.cross { color: var(--danger); font-weight: 800; float: right; }