:root {
    --surface-glass: rgba(8, 27, 50, .78);
    --surface-raised: rgba(14, 42, 73, .88);
    --line-soft: rgba(130, 190, 235, .18);
    --shadow-soft: 0 18px 48px rgba(0, 8, 24, .24);
    --shadow-hover: 0 22px 55px rgba(0, 14, 40, .34);
    --radius-xl: 22px;
}

html { scroll-behavior: smooth; }
body {
    background:
        radial-gradient(circle at 10% 0%, rgba(0, 194, 255, .10), transparent 30rem),
        radial-gradient(circle at 92% 8%, rgba(124, 92, 255, .12), transparent 32rem),
        var(--background, #020817);
}
body::before {
    content: "";
    position: fixed;
    inset: 0;
    z-index: -1;
    pointer-events: none;
    background-image: linear-gradient(rgba(255,255,255,.018) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.018) 1px, transparent 1px);
    background-size: 42px 42px;
    mask-image: linear-gradient(to bottom, #000, transparent 75%);
}

.student-sidebar, .sidebar {
    backdrop-filter: blur(18px);
    border-right: 1px solid var(--line-soft);
    box-shadow: 12px 0 38px rgba(0, 8, 24, .18);
}
.student-sidebar nav a, .sidebar nav a, .student-tab-nav button {
    display: flex;
    align-items: center;
    gap: 11px;
    transition: transform .18s ease, background .18s ease, color .18s ease;
}
.student-sidebar nav a:hover, .sidebar nav a:hover, .student-tab-nav button:hover { transform: translateX(3px); }
.nav-icon, .metric-icon { width: 19px; height: 19px; stroke-width: 2; flex: 0 0 auto; }

.student-header, .student-panel, .panel, .metric-card, .coach-student-card {
    border: 1px solid var(--line-soft);
    box-shadow: var(--shadow-soft);
}
.student-header, .student-panel, .panel {
    background: linear-gradient(145deg, var(--surface-glass), rgba(6, 21, 41, .92));
    backdrop-filter: blur(14px);
    border-radius: var(--radius-xl);
}
.metric-card {
    position: relative;
    overflow: hidden;
    min-height: 142px;
    border-radius: 19px;
    transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}
.metric-card::after {
    content: "";
    position: absolute;
    width: 110px;
    height: 110px;
    right: -42px;
    top: -46px;
    border-radius: 50%;
    background: currentColor;
    opacity: .07;
}
.metric-card:hover, .coach-student-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); border-color: rgba(80, 210, 255, .35); }
.metric-card .metric-icon { margin-bottom: 13px; opacity: .9; }
.metric-card strong { letter-spacing: -.04em; }

.section-heading h2, .student-header h1 { letter-spacing: -.035em; }
.section-heading { align-items: center; }
.eyebrow { letter-spacing: .13em; }
button, .button-link, input, select, textarea { transition: border-color .18s ease, box-shadow .18s ease, transform .18s ease; }
button:hover, .button-link:hover { transform: translateY(-1px); }
input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: #28c8ff !important;
    box-shadow: 0 0 0 4px rgba(40, 200, 255, .12);
}

.insight-chart-card { margin-top: 20px; }
.chart-shell { position: relative; min-height: 300px; padding: 12px 4px 2px; }
.chart-shell canvas { width: 100% !important; height: 290px !important; }
.dashboard-insight-grid { display: grid; grid-template-columns: minmax(0, 1.6fr) minmax(260px, .7fr); gap: 18px; margin-top: 20px; }
.insight-summary { display: grid; gap: 12px; }
.insight-summary article { padding: 16px; border-radius: 15px; background: rgba(15, 51, 85, .58); border: 1px solid var(--line-soft); }
.insight-summary strong, .insight-summary small { display: block; }
.insight-summary strong { font-size: 1.45rem; margin-top: 5px; }

.table-wrap, .leaderboard-wrap { border-radius: 16px; overflow: auto; border: 1px solid var(--line-soft); }
table { border-collapse: separate; border-spacing: 0; }
thead th { position: sticky; top: 0; z-index: 2; backdrop-filter: blur(10px); }
.empty-state { border: 1px dashed rgba(120, 190, 230, .28); border-radius: 16px; }

@media (max-width: 900px) {
    .dashboard-insight-grid { grid-template-columns: 1fr; }
    .chart-shell { min-height: 250px; }
    .chart-shell canvas { height: 240px !important; }
}
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; animation-duration: .01ms !important; }
}

.activity-hero { margin-bottom: 18px; overflow: hidden; position: relative; }
.activity-progress { height: 12px; margin-top: 18px; overflow: hidden; border-radius: 999px; background: rgba(4, 18, 35, .8); }
.activity-progress i { display: block; height: 100%; border-radius: inherit; background: linear-gradient(90deg, #23d5ff, #7d6cff, #28d89b); }
.activity-week-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.activity-card { padding: 20px; border: 1px solid var(--line-soft); border-radius: 19px; background: linear-gradient(145deg, rgba(11, 37, 65, .92), rgba(5, 20, 40, .94)); box-shadow: var(--shadow-soft); }
.activity-card.completed { opacity: .72; border-color: rgba(40, 216, 155, .4); }
.activity-card header, .activity-actions, .activity-metrics { display: flex; align-items: center; justify-content: space-between; gap: 10px; flex-wrap: wrap; }
.activity-day, .activity-priority { padding: 6px 10px; border-radius: 999px; font-size: .78rem; font-weight: 800; }
.activity-day { color: #081525; background: #4cddff; }
.activity-priority { color: #d9ccff; background: rgba(125, 108, 255, .18); border: 1px solid rgba(125, 108, 255, .28); }
.activity-card h3 { margin: 13px 0 3px; font-size: 1.3rem; }
.activity-topic { color: #5edfff; font-weight: 750; margin-top: 0; }
.activity-metrics { justify-content: flex-start; margin: 16px 0; }
.activity-metrics span { padding: 9px 11px; border-radius: 11px; background: rgba(17, 58, 93, .72); font-size: .86rem; }
.activity-actions { border-top: 1px solid var(--line-soft); padding-top: 14px; }
.video-link { color: #69e3ff; text-decoration: none; font-weight: 700; }
.activity-done { color: #47dda5; font-weight: 800; }
.activity-complete-form { margin-top: 16px; padding-top: 16px; border-top: 1px solid var(--line-soft); }
.pomodoro-dock { position: sticky; bottom: 16px; z-index: 30; display: grid; grid-template-columns: 1fr auto auto; align-items: center; gap: 22px; margin-top: 20px; border-color: rgba(45, 213, 255, .52); box-shadow: 0 18px 70px rgba(0, 0, 0, .48); }
.pomodoro-dock[hidden] { display: none; }
.pomodoro-clock { min-width: 150px; font-size: clamp(2.2rem, 6vw, 4.4rem); font-variant-numeric: tabular-nums; font-weight: 850; letter-spacing: -.07em; color: #70e7ff; text-align: center; }
.pomodoro-controls { display: grid; gap: 9px; }
@media (max-width: 800px) { .activity-week-grid { grid-template-columns: 1fr; } .pomodoro-dock { grid-template-columns: 1fr; text-align: center; } .pomodoro-controls { grid-template-columns: 1fr 1fr; } }
.exam-type-tabs { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; padding: 6px; border-radius: 14px; background: rgba(4, 18, 35, .72); border: 1px solid var(--line-soft); }
.exam-type-tabs button { padding: 11px 8px; border: 0; border-radius: 10px; background: transparent; color: #a9bdd0; font-weight: 750; }
.exam-type-tabs button.active { color: #071522; background: linear-gradient(135deg, #4cddff, #69f1c1); box-shadow: 0 8px 22px rgba(38, 205, 255, .2); }
.custom-exam-fields { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; padding: 14px; border-radius: 14px; border: 1px solid rgba(125, 108, 255, .28); background: rgba(125, 108, 255, .08); }
@media (max-width: 650px) { .exam-type-tabs { grid-template-columns: 1fr 1fr; } .custom-exam-fields { grid-template-columns: 1fr; } }
.activity-week-tabs { display: flex; gap: 8px; overflow-x: auto; padding: 4px 2px 13px; margin-bottom: 8px; scrollbar-width: thin; }
.activity-week-tabs button { flex: 0 0 auto; min-width: 105px; padding: 11px 14px; border-radius: 12px; border: 1px solid var(--line-soft); background: rgba(8, 29, 52, .85); color: #a9bdd0; }
.activity-week-tabs button.active { color: #071522; background: linear-gradient(135deg, #4cddff, #6cf0b4); border-color: transparent; font-weight: 800; }
.activity-card button:disabled { cursor: not-allowed; opacity: .55; transform: none; }
.format-options { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 10px; padding: 14px; border: 1px solid var(--line-soft); border-radius: 14px; }
.format-options legend { padding: 0 7px; color: #72e3ff; font-weight: 800; }
.format-options label { display: flex; align-items: center; gap: 8px; }
.format-options input { width: auto; }
.video-link { border: 0; padding: 8px 0; background: transparent; }
.video-modal { position: fixed; inset: 0; z-index: 1000; display: grid; place-items: center; padding: 22px; background: rgba(0, 7, 18, .82); backdrop-filter: blur(12px); }
.video-modal[hidden] { display: none; }
.video-modal-card { width: min(920px, 100%); max-height: 92vh; overflow: auto; padding: 22px; border-radius: 22px; background: #07182d; border: 1px solid rgba(80, 210, 255, .35); box-shadow: 0 30px 90px rgba(0,0,0,.65); }
.video-modal-card > header { display: flex; justify-content: space-between; gap: 18px; align-items: flex-start; }
.video-modal-card > header button { width: 42px; height: 42px; border-radius: 50%; padding: 0; font-size: 1.7rem; }
.video-frame { aspect-ratio: 16/9; margin-top: 16px; overflow: hidden; border-radius: 16px; background: #020814; }
.video-frame iframe { width: 100%; height: 100%; border: 0; }
.video-frame .empty-state { height: 100%; display: grid; place-items: center; text-align: center; padding: 25px; }
.video-modal-actions { display: flex; justify-content: flex-end; margin-top: 14px; }
.video-modal-actions a { padding: 10px 14px; border-radius: 11px; color: #071522; background: #4cddff; text-decoration: none; font-weight: 800; }
.program-update { margin-top: 18px; border-top: 1px solid var(--line-soft); padding-top: 14px; }
.program-update summary { cursor: pointer; color: #70e7ff; font-weight: 800; }
.program-update form { margin-top: 14px; }