:root {
    --bg: #f3f5f9;
    --panel: #ffffff;
    --text: #1f2937;
    --muted: #6b7280;
    --accent: #0f766e;
    --accent-dark: #115e59;
    --border: #dbe1ea;
    --danger: #b42318;
    --warning: #b54708;
    --success: #067647;
    --shadow: 0 12px 24px rgba(15, 23, 42, 0.06);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    color: var(--text);
    background:
        radial-gradient(circle at top right, rgba(15, 118, 110, 0.12), transparent 30%),
        linear-gradient(180deg, #eef7f5 0%, var(--bg) 32%, var(--bg) 100%);
}

a {
    color: var(--accent);
    text-decoration: none;
}

a:hover {
    color: var(--accent-dark);
}

.site-shell {
    min-height: 100vh;
    display: grid;
    grid-template-columns: 260px 1fr;
}

.site-shell.no-sidebar {
    grid-template-columns: 1fr;
}

.sidebar {
    background: linear-gradient(180deg, #0f172a 0%, #111827 100%);
    color: #ffffff;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.sidebar-brand {
    font-size: 1.2rem;
    font-weight: 700;
}

.sidebar-nav,
.sidebar-section {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.sidebar-heading {
    font-size: 0.8rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: #94a3b8;
    margin-top: 0.5rem;
}

.sidebar a {
    color: #e2e8f0;
    padding: 0.55rem 0.75rem;
    border-radius: 0.5rem;
}

.sidebar a:hover {
    background: rgba(255, 255, 255, 0.08);
    color: #ffffff;
}

.main-column {
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.78);
    backdrop-filter: blur(8px);
    position: sticky;
    top: 0;
    z-index: 10;
}

.topbar-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.content {
    padding: 1.5rem;
}

.site-footer {
    padding: 1rem 1.5rem 2rem;
    color: var(--muted);
}

.card,
.stat-grid .stat-card,
.question-card,
.review-card {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 1rem;
    box-shadow: var(--shadow);
    padding: 1.25rem;
    margin-bottom: 1rem;
}

.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
    margin-bottom: 1rem;
}

.stat-label {
    color: var(--muted);
    font-size: 0.9rem;
}

.stat-value {
    font-size: 1.7rem;
    font-weight: 700;
    margin-top: 0.25rem;
}

.button,
button,
input[type="submit"] {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 0;
    border-radius: 0.65rem;
    background: var(--accent);
    color: #ffffff;
    padding: 0.7rem 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s ease;
}

.button:hover,
button:hover,
input[type="submit"]:hover {
    background: var(--accent-dark);
    color: #ffffff;
}

.button.secondary,
button.secondary {
    background: #e5e7eb;
    color: var(--text);
}

.button.secondary:hover,
button.secondary:hover {
    background: #d1d5db;
}

.button.danger,
button.danger {
    background: var(--danger);
}

.button.warning,
button.warning {
    background: var(--warning);
}

form {
    margin: 0;
}

.form-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1rem;
}

.form-row {
    margin-bottom: 1rem;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.4rem;
}

input[type="text"],
input[type="email"],
input[type="password"],
input[type="number"],
textarea,
select {
    width: 100%;
    border: 1px solid var(--border);
    border-radius: 0.7rem;
    padding: 0.75rem 0.85rem;
    font: inherit;
    background: #ffffff;
}

textarea {
    min-height: 120px;
    resize: vertical;
}

.inline-form {
    display: inline-flex;
    gap: 0.5rem;
    align-items: center;
    flex-wrap: wrap;
}

.checkbox-row,
.radio-row {
    display: flex;
    gap: 0.75rem;
    align-items: center;
    margin-bottom: 0.6rem;
    flex-wrap: wrap;
}

.checkbox-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 0.45rem 1rem;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: var(--panel);
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow);
}

th,
td {
    padding: 0.9rem;
    border-bottom: 1px solid var(--border);
    text-align: left;
    vertical-align: top;
}

th {
    background: #f8fafc;
    font-size: 0.92rem;
}

tr:last-child td {
    border-bottom: 0;
}

.table-actions {
    display: flex;
    gap: 0.4rem;
    flex-wrap: wrap;
}

.flash {
    border-radius: 0.8rem;
    padding: 0.9rem 1rem;
    margin-bottom: 1rem;
    border: 1px solid transparent;
}

.flash-success {
    background: #ecfdf3;
    color: var(--success);
    border-color: #abefc6;
}

.flash-error {
    background: #fef3f2;
    color: var(--danger);
    border-color: #fecdca;
}

.flash-info {
    background: #eff8ff;
    color: #175cd3;
    border-color: #b2ddff;
}

.muted {
    color: var(--muted);
}

.split-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.options-list {
    display: grid;
    gap: 0.75rem;
}

.option-item {
    border: 1px solid var(--border);
    border-radius: 0.8rem;
    padding: 0.85rem;
    background: #ffffff;
}

.option-item.correct {
    border-color: #12b76a;
    background: #ecfdf3;
}

.option-item.incorrect {
    border-color: #f04438;
    background: #fef3f2;
}

.option-item.selected {
    box-shadow: inset 0 0 0 1px var(--accent);
}

.drag-list {
    list-style: none;
    margin: 0.75rem 0 0;
    padding: 0;
    display: grid;
    gap: 0.6rem;
}

.drag-item {
    display: flex;
    align-items: flex-start;
    gap: 0.7rem;
    border: 1px solid var(--border);
    border-radius: 0.8rem;
    background: #ffffff;
    padding: 0.8rem 0.85rem;
    cursor: move;
}

.drag-item .markdown-body {
    margin: 0;
    flex: 1;
}

.drag-item.dragging {
    opacity: 0.65;
    border-color: var(--accent);
}

.drag-handle {
    color: var(--muted);
    font-size: 1.05rem;
    line-height: 1.2;
    margin-top: 0.1rem;
}

.exam-step-locked .drag-item {
    background: #f8fafc;
    cursor: not-allowed;
}

.drag-review-status {
    font-weight: 700;
    margin-bottom: 0.65rem;
}

.drag-review-status.is-correct {
    color: var(--success);
}

.drag-review-status.is-incorrect {
    color: var(--danger);
}

.drag-review-grid {
    display: grid;
    gap: 0.75rem;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.drag-review-card {
    border: 1px solid var(--border);
    border-radius: 0.8rem;
    padding: 0.85rem;
    background: #ffffff;
}

.drag-review-card h4 {
    margin-top: 0;
}

.drag-review-card ol {
    margin: 0;
    padding-left: 1.2rem;
}

.markdown-body p,
.markdown-body ul,
.markdown-body ol,
.markdown-body blockquote,
.markdown-body pre {
    margin-top: 0;
}

.markdown-body pre {
    background: #0f172a;
    color: #e2e8f0;
    padding: 0.9rem;
    border-radius: 0.7rem;
    overflow-x: auto;
}

.badge {
    display: inline-block;
    background: #ecfeff;
    color: #155e75;
    padding: 0.25rem 0.55rem;
    border-radius: 999px;
    font-size: 0.8rem;
    margin-right: 0.35rem;
    margin-bottom: 0.35rem;
}

.danger-text {
    color: var(--danger);
}

.success-text {
    color: var(--success);
}

.warning-text {
    color: var(--warning);
}

.question-image {
    max-width: 100%;
    height: auto;
    border-radius: 0.8rem;
    border: 1px solid var(--border);
    margin: 0.75rem 0;
}

.exam-flow-progress {
    color: var(--muted);
    font-size: 0.92rem;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.exam-flow-form {
    padding-bottom: 8rem;
}

.exam-sticky-nav {
    position: fixed;
    right: 1.5rem;
    bottom: 1.25rem;
    z-index: 40;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    background: rgba(17, 24, 39, 0.94);
    border: 1px solid rgba(255, 255, 255, 0.16);
    border-radius: 999px;
    box-shadow: 0 18px 32px rgba(15, 23, 42, 0.35);
    padding: 0.55rem 0.65rem 0.55rem 1rem;
}

.exam-sticky-note {
    color: #e5e7eb;
    font-size: 0.85rem;
    white-space: nowrap;
}

.exam-sticky-next {
    min-width: 190px;
    padding: 0.85rem 1.2rem;
    font-size: 1rem;
    font-weight: 700;
    border-radius: 999px;
    box-shadow: 0 8px 18px rgba(15, 118, 110, 0.35);
}

.exam-sticky-next:disabled {
    background: #94a3b8;
    cursor: not-allowed;
    box-shadow: none;
}

.exam-flow-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

.exam-flow-hint {
    color: var(--muted);
}

.exam-timer {
    position: sticky;
    top: 5.5rem;
    background: #111827;
    color: #ffffff;
    padding: 0.75rem 1rem;
    border-radius: 0.8rem;
    margin-bottom: 1rem;
    display: inline-block;
}

.sparkline svg {
    width: 120px;
    height: 32px;
    display: block;
}

.sparkline path {
    fill: none;
    stroke: var(--accent);
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.auth-card {
    max-width: 540px;
    margin: 2rem auto;
}

@media (max-width: 960px) {
    .site-shell {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
    }

    .topbar {
        position: static;
    }
}

@media (max-width: 640px) {
    .content,
    .topbar,
    .site-footer {
        padding-left: 1rem;
        padding-right: 1rem;
    }

    th,
    td {
        padding: 0.75rem;
    }

    .exam-flow-form {
        padding-bottom: 7.5rem;
    }

    .exam-sticky-nav {
        left: 0.75rem;
        right: 0.75rem;
        bottom: 0.75rem;
        border-radius: 1rem;
        justify-content: space-between;
        gap: 0.7rem;
    }

    .exam-sticky-note {
        display: none;
    }

    .exam-sticky-next {
        min-width: 0;
        width: 100%;
    }
}