/* =============================================
   COMPARE PAGE — Premium Exam Comparison UI
   ============================================= */

@import url('../vendor/inter/inter.css');

:root {
    --bg-color: #f0f2f5;
    --text-color: #1a1a2e;
    --text-secondary: #6c7a89;
    --card-bg: rgba(255, 255, 255, 0.85);
    --card-bg-solid: #fff;
    --border-color: rgba(0, 0, 0, 0.06);
    --primary: #667eea;
    --primary-light: #7c93f7;
    --accent-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --accent-gradient-2: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --accent-gradient-3: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.1);
    --shadow-glow: 0 0 30px rgba(102, 126, 234, 0.15);
    --glass-bg: rgba(255, 255, 255, 0.6);
    --glass-border: rgba(255, 255, 255, 0.3);
    --improvement: #00b894;
    --regression: #ff6b6b;
    --neutral: #a29bfe;
    --radius: 16px;
    --radius-sm: 10px;
}

[data-theme="dark"] {
    --bg-color: #0a0a14;
    --text-color: #e8e8f0;
    --text-secondary: #8888a0;
    --card-bg: rgba(26, 26, 46, 0.8);
    --card-bg-solid: #1a1a2e;
    --border-color: rgba(255, 255, 255, 0.06);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 40px rgba(102, 126, 234, 0.12);
    --glass-bg: rgba(26, 26, 46, 0.7);
    --glass-border: rgba(255, 255, 255, 0.08);
}

* { box-sizing: border-box; }

body {
    font-family: 'Inter', 'Segoe UI', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    transition: background-color 0.4s, color 0.4s;
    min-height: 100vh;
}

/* Animated background orbs */
body::before,
body::after {
    content: '';
    position: fixed;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.12;
    pointer-events: none;
    z-index: 0;
    animation: floatOrb 20s ease-in-out infinite;
}

body::before {
    width: 500px;
    height: 500px;
    background: var(--accent-gradient);
    top: -150px;
    right: -100px;
}

body::after {
    width: 400px;
    height: 400px;
    background: var(--accent-gradient-3);
    bottom: -100px;
    left: -100px;
    animation-delay: -10s;
}

@keyframes floatOrb {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, -20px) scale(1.05); }
    66% { transform: translate(-20px, 15px) scale(0.95); }
}

.compare-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px 50px;
    position: relative;
    z-index: 1;
}

/* =============================================
   NAV BAR — Glassmorphism
   ============================================= */
.compare-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: linear-gradient(135deg, rgba(44, 62, 80, 0.95), rgba(52, 73, 94, 0.95));
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 12px 22px;
    border-radius: var(--radius);
    margin-bottom: 20px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: var(--shadow-md);
}

.compare-nav h2 {
    margin: 0;
    color: #fff;
    font-size: 16px;
    font-weight: 700;
    letter-spacing: -0.2px;
}

.nav-btn {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.15);
    padding: 7px 14px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-size: 12px;
    font-weight: 600;
    transition: all 0.25s ease;
}

.nav-btn:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-1px);
}

/* =============================================
   MODE TABS — Pill style
   ============================================= */
.mode-tabs {
    display: flex;
    gap: 0;
    margin-bottom: 20px;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 14px;
    padding: 5px;
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-sm);
}

.mode-tab {
    flex: 1;
    padding: 11px 16px;
    border: none;
    background: none;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: 10px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-family: inherit;
}

.mode-tab:hover {
    color: var(--text-color);
    background: rgba(102, 126, 234, 0.06);
}

.mode-tab.active {
    background: var(--accent-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.35);
    transform: scale(1.01);
}

/* =============================================
   SELECTOR SECTION — Glass card
   ============================================= */
.selector-section {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 24px;
    border-radius: var(--radius);
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-md);
    margin-bottom: 24px;
}

.selector-section h3 {
    margin: 0 0 4px 0;
    font-size: 17px;
    font-weight: 700;
    color: var(--text-color);
}

.selector-section .subtitle {
    font-size: 13px;
    color: var(--text-secondary);
    margin: 0 0 18px 0;
}

/* Re-attempted exam cards */
.reattempt-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 12px;
}

.reattempt-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 14px;
    padding: 16px 18px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.reattempt-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--accent-gradient);
    opacity: 0;
    transition: opacity 0.3s;
}

.reattempt-card:hover {
    border-color: rgba(102, 126, 234, 0.3);
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.reattempt-card:hover::before {
    opacity: 1;
}

.reattempt-card.selected {
    border-color: var(--primary);
    background: rgba(102, 126, 234, 0.05);
}

.reattempt-card-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 10px;
}

.reattempt-title {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-color);
    line-height: 1.35;
    flex: 1;
    min-width: 0;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.reattempt-meta {
    display: flex;
    gap: 14px;
    font-size: 12px;
    color: var(--text-secondary);
}

.reattempt-meta span {
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.attempt-badge {
    display: inline-block;
    background: var(--accent-gradient);
    color: white;
    font-size: 10px;
    font-weight: 700;
    padding: 3px 10px;
    border-radius: 20px;
    flex-shrink: 0;
    letter-spacing: 0.3px;
    text-transform: uppercase;
    white-space: nowrap;
    line-height: 1.4;
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.3);
}

/* Manual selector */
.exam-search-input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--card-bg);
    color: var(--text-color);
    font-size: 14px;
    font-family: inherit;
    margin-bottom: 12px;
    transition: all 0.25s;
    outline: none;
}

.exam-search-input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
}

.exam-checkbox-list {
    max-height: 300px;
    overflow-y: auto;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 6px;
    background: var(--card-bg);
}

.exam-checkbox-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.15s;
}

.exam-checkbox-item:hover {
    background: rgba(102, 126, 234, 0.06);
}

.exam-checkbox-item input[type="checkbox"] {
    accent-color: var(--primary);
    width: 16px;
    height: 16px;
    cursor: pointer;
}

.exam-checkbox-item label {
    flex: 1;
    cursor: pointer;
    font-size: 13px;
    font-weight: 500;
}

.exam-checkbox-item .exam-date-small {
    font-size: 11px;
    color: var(--text-secondary);
    white-space: nowrap;
}

.compare-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    background: var(--accent-gradient);
    color: white;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 700;
    font-family: inherit;
    cursor: pointer;
    margin-top: 14px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.compare-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(102, 126, 234, 0.45);
}

.compare-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    box-shadow: none;
}

/* =============================================
   COMPARISON RESULTS
   ============================================= */
.compare-results {
    display: none;
}

.compare-results.visible {
    display: block;
    animation: slideUp 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* =============================================
   SUMMARY CARDS — Animated gradient borders
   ============================================= */
.summary-cards-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 14px;
    margin-bottom: 24px;
}

.attempt-summary-card {
    background: var(--card-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--radius);
    padding: 22px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.attempt-summary-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--accent-gradient);
}

.attempt-summary-card:nth-child(2)::after { background: var(--accent-gradient-2); }
.attempt-summary-card:nth-child(3)::after { background: var(--accent-gradient-3); }
.attempt-summary-card:nth-child(4)::after { background: linear-gradient(135deg, #f093fb, #f5576c); }

.attempt-summary-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.attempt-label {
    font-size: 10px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 1.2px;
    color: white;
    background: var(--accent-gradient);
    display: inline-block;
    padding: 4px 12px;
    border-radius: 6px;
    margin-bottom: 10px;
}

.attempt-summary-card:nth-child(2) .attempt-label { background: var(--accent-gradient-2); }
.attempt-summary-card:nth-child(3) .attempt-label { background: var(--accent-gradient-3); color: #1a1a2e; }

.attempt-date {
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: 14px;
    font-weight: 500;
}

.attempt-stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 8px;
}

.attempt-stat {
    text-align: center;
    padding: 10px 6px;
    background: rgba(102, 126, 234, 0.04);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
    transition: transform 0.2s;
}

.attempt-stat:hover {
    transform: scale(1.03);
}

.attempt-stat-value {
    font-size: 18px;
    font-weight: 800;
    line-height: 1.2;
    letter-spacing: -0.5px;
}

.attempt-stat-label {
    font-size: 9px;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    color: var(--text-secondary);
    font-weight: 700;
    margin-top: 3px;
}

.stat-score { color: #667eea; }
.stat-accuracy { color: #00b894; }
.stat-correct { color: #27ae60; }
.stat-incorrect { color: #ff6b6b; }
.stat-unattempted { color: #a29bfe; }
.stat-time { color: #fdcb6e; }

/* Progress arrows */
.progress-arrow {
    display: inline-flex;
    align-items: center;
    gap: 2px;
    font-size: 10px;
    font-weight: 700;
    padding: 2px 6px;
    border-radius: 6px;
    margin-left: 4px;
    vertical-align: middle;
}

.progress-arrow.up {
    color: var(--improvement);
    background: rgba(0, 184, 148, 0.12);
}

.progress-arrow.down {
    color: var(--regression);
    background: rgba(255, 107, 107, 0.12);
}

.progress-arrow.same {
    color: var(--neutral);
    background: rgba(162, 155, 254, 0.12);
}

/* =============================================
   CHARTS — Clean cards with subtle depth
   ============================================= */
.compare-charts-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px;
    margin-bottom: 24px;
}

@media (max-width: 768px) {
    .compare-charts-grid { grid-template-columns: 1fr; }
}

.compare-chart-card {
    background: var(--card-bg);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    padding: 20px;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    transition: box-shadow 0.3s, transform 0.3s;
}

.compare-chart-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.compare-chart-card.full-width {
    grid-column: 1 / -1;
}

.compare-chart-title {
    font-size: 14px;
    font-weight: 700;
    margin: 0 0 14px 0;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-color);
}

.compare-chart-wrapper {
    position: relative;
    height: 260px;
    width: 100%;
}

/* =============================================
   DIFF TABLE — Clean, minimal
   ============================================= */
.diff-section {
    background: var(--card-bg);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
    overflow: hidden;
}

.diff-section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: 10px;
}

.diff-section-header h3 {
    margin: 0;
    font-size: 15px;
    font-weight: 700;
    color: var(--text-color);
}

.diff-filter-bar {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.diff-filter-btn {
    padding: 5px 12px;
    border: 1px solid var(--border-color);
    background: none;
    border-radius: 8px;
    font-size: 11px;
    font-weight: 600;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all 0.2s;
    font-family: inherit;
}

.diff-filter-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: rgba(102, 126, 234, 0.05);
}

.diff-filter-btn.active {
    background: var(--accent-gradient);
    color: white;
    border-color: transparent;
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.25);
}

.diff-table-wrapper {
    overflow-x: auto;
    max-height: 500px;
    overflow-y: auto;
}

.diff-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13px;
}

.diff-table thead {
    position: sticky;
    top: 0;
    z-index: 2;
}

.diff-table thead th {
    background: linear-gradient(135deg, #2c3e50, #34495e);
    color: rgba(255, 255, 255, 0.9);
    padding: 11px 14px;
    text-align: center;
    font-weight: 600;
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    white-space: nowrap;
}

[data-theme="dark"] .diff-table thead th {
    background: linear-gradient(135deg, #16213e, #1a1a3e);
}

.diff-table thead th:first-child {
    text-align: left;
    position: sticky;
    left: 0;
    z-index: 3;
}

.diff-table tbody td {
    padding: 9px 14px;
    border-bottom: 1px solid var(--border-color);
    text-align: center;
    vertical-align: middle;
}

.diff-table tbody td:first-child {
    text-align: left;
    font-weight: 700;
    font-size: 12px;
    position: sticky;
    left: 0;
    background: var(--card-bg-solid);
    z-index: 1;
    min-width: 60px;
    color: var(--text-secondary);
}

.diff-table tbody tr {
    transition: background 0.15s;
}

.diff-table tbody tr:hover td {
    background: rgba(102, 126, 234, 0.04);
}

.diff-table tbody tr:hover td:first-child {
    background: rgba(102, 126, 234, 0.06);
}

.diff-table tbody tr.highlight-flip {
    background: rgba(253, 203, 110, 0.06);
}

/* Status badges */
.status-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 30px;
    height: 30px;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 700;
    transition: transform 0.15s;
}

.status-badge:hover {
    transform: scale(1.15);
}

.status-badge.correct {
    background: rgba(0, 184, 148, 0.12);
    color: #00b894;
}

.status-badge.incorrect {
    background: rgba(255, 107, 107, 0.12);
    color: #ff6b6b;
}

.status-badge.unanswered {
    background: rgba(162, 155, 254, 0.12);
    color: #a29bfe;
}

.flip-badge {
    display: inline-block;
    font-size: 9px;
    font-weight: 800;
    padding: 2px 6px;
    border-radius: 4px;
    margin-left: 4px;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    animation: popIn 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes popIn {
    from { transform: scale(0.6); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

.flip-badge.improved {
    background: rgba(0, 184, 148, 0.12);
    color: #00b894;
}

.flip-badge.regressed {
    background: rgba(255, 107, 107, 0.12);
    color: #ff6b6b;
}

/* =============================================
   AI INSIGHTS — Premium card
   ============================================= */
.insights-card {
    background: var(--card-bg);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    padding: 22px;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
    position: relative;
    overflow: hidden;
}

.insights-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, #667eea, #764ba2, #f093fb, #f5576c, #4facfe, #00f2fe);
    background-size: 300% 100%;
    animation: shimmer 4s ease infinite;
}

@keyframes shimmer {
    0% { background-position: 0% 0; }
    50% { background-position: 100% 0; }
    100% { background-position: 0% 0; }
}

.insights-card h3 {
    margin: 0 0 14px 0;
    font-size: 15px;
    font-weight: 700;
    color: var(--text-color);
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
}

.insight-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 12px 0;
    border-bottom: 1px dashed var(--border-color);
    line-height: 1.55;
}

.insight-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.insight-icon {
    font-size: 18px;
    flex-shrink: 0;
    margin-top: 1px;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(102, 126, 234, 0.06);
    border-radius: 8px;
}

.insight-text {
    font-size: 13px;
    color: var(--text-color);
}

.insight-text strong {
    color: var(--primary);
}

/* =============================================
   EMPTY STATE
   ============================================= */
.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-secondary);
}

.empty-state .empty-icon {
    font-size: 40px;
    margin-bottom: 12px;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

.empty-state h3 {
    font-size: 16px;
    margin-bottom: 6px;
    color: var(--text-color);
}

.empty-state p {
    font-size: 13px;
    max-width: 360px;
    margin: 0 auto;
    line-height: 1.5;
}

/* =============================================
   LOADING SPINNER
   ============================================= */
.compare-loading {
    display: none;
    text-align: center;
    padding: 40px;
}

.compare-loading.visible {
    display: block;
}

.compare-loading p {
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 500;
}

.spinner {
    width: 36px;
    height: 36px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
    margin: 0 auto 12px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* =============================================
   RESPONSIVE
   ============================================= */
@media (max-width: 600px) {
    .compare-container { padding: 0 12px 30px; }
    .compare-nav { flex-direction: column; gap: 8px; text-align: center; padding: 12px 16px; }
    .summary-cards-row { grid-template-columns: 1fr; }
    .reattempt-grid { grid-template-columns: 1fr; }
    .mode-tabs { flex-direction: column; }
    .selector-section { padding: 16px; }
    .attempt-stats-grid { grid-template-columns: 1fr 1fr; }
    .diff-filter-bar { flex-wrap: wrap; }
    .diff-section-header { flex-direction: column; align-items: flex-start; }
}

/* Custom scrollbar */
.diff-table-wrapper::-webkit-scrollbar,
.exam-checkbox-list::-webkit-scrollbar {
    width: 5px;
    height: 5px;
}

.diff-table-wrapper::-webkit-scrollbar-thumb,
.exam-checkbox-list::-webkit-scrollbar-thumb {
    background: rgba(102, 126, 234, 0.25);
    border-radius: 3px;
}

.diff-table-wrapper::-webkit-scrollbar-track,
.exam-checkbox-list::-webkit-scrollbar-track {
    background: transparent;
}