:root {
    --bg-color: #0f172a;
    --sidebar-bg: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #38bdf8;
    --accent-hover: #0ea5e9;
    --border-color: #334155;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --input-bg: #0f172a;

    --font-main: 'Outfit', sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-main);
    background-color: var(--bg-color);
    color: var(--text-primary);
    overflow: hidden;
    /* App-like feel */
    height: 100vh;
}

.app-container {
    display: flex;
    height: 100%;
}

/* Sidebar */
.sidebar {
    width: 320px;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    overflow-y: auto;
}

.logo-area {
    margin-bottom: 2rem;
}

.logo-area h1 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
}

.highlight {
    color: var(--accent-color);
}

.subtitle {
    font-size: 0.85rem;
    color: var(--text-secondary);
    letter-spacing: 1px;
    text-transform: uppercase;
}

/* Controls */
.controls {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.control-group label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.premium-select,
.search-input {
    background-color: var(--input-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.75rem;
    border-radius: 8px;
    font-family: var(--font-main);
    font-size: 0.95rem;
    outline: none;
    transition: border-color 0.2s;
}

.premium-select:focus,
.search-input:focus {
    border-color: var(--accent-color);
}

.multi-select-container {
    background-color: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    max-height: 200px;
    display: flex;
    flex-direction: column;
}

.multi-select-container .search-input {
    border: none;
    border-bottom: 1px solid var(--border-color);
    border-radius: 8px 8px 0 0;
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
}

.checkbox-list {
    overflow-y: auto;
    padding: 0.5rem;
    flex: 1;
}

.checkbox-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.25rem 0.5rem;
    font-size: 0.85rem;
    cursor: pointer;
    border-radius: 4px;
}

.checkbox-item:hover {
    background-color: rgba(255, 255, 255, 0.05);
}

/* View Save/Load */
.view-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.view-btn {
    flex: 1;
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 0.4rem 0.5rem;
    border-radius: 8px;
    font-family: var(--font-main);
    font-size: 0.78rem;
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.view-btn:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
}

.sidebar-footer {
    margin-top: auto;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
    font-size: 0.75rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.sidebar-footer p {
    margin: 0;
}

.sidebar-footer strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    position: relative;
    background: radial-gradient(circle at top right, #1e293b 0%, #0f172a 40%);
    overflow-y: auto;
    /* Allow the page to scroll when content grows */
}

.top-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.top-bar .actions {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.glass-panel {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
    border-radius: 16px;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
    overflow: visible;
    /* Content can scroll within main-content */
    position: relative;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    flex: 0 0 auto;
    /* Allow natural height based on content */
}

/* Split View Layout */
.chart-split-wrapper {
    display: flex;
    gap: 1rem;
    flex: 0 0 auto;
    /* Prevent shrinking */
    min-height: 0;
    margin-bottom: 0.5rem;
}

.chart-panel {
    display: flex;
    flex-direction: column;
    min-width: 0;
    flex: 1;
}

.chart-panel-header {
    height: 42px;
    /* Fixed height for symmetry */
    margin-bottom: 0.5rem;
    display: none;
    /* Hidden by default, shown in compare mode via JS */
    align-items: center;
}

.chart-subject-select {
    background: var(--glass-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.4rem 0.8rem;
    border-radius: 8px;
    font-family: var(--font-main);
    font-size: 0.82rem;
    cursor: pointer;
    outline: none;
    transition: border-color 0.2s ease;
}

.chart-subject-select:hover,
.chart-subject-select:focus {
    border-color: var(--accent-color);
}

.graph-area {
    height: 720px;
    /* Maximum fixed height for best readability */
    width: 100%;
    position: relative;
}

/* Chart Tooltip */
.chart-tooltip {
    position: absolute;
    z-index: 10;
    background: rgba(15, 23, 42, 0.95);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 10px 14px;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.15s ease;
    font-family: var(--font-main);
    font-size: 0.8rem;
    color: var(--text-primary);
    white-space: nowrap;
    backdrop-filter: blur(8px);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.tooltip-header {
    font-weight: 600;
    color: var(--accent-color);
    margin-bottom: 6px;
    font-size: 0.78rem;
}

.tooltip-row {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 2px 0;
}

.tooltip-dot {
    display: inline-block;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    flex-shrink: 0;
}

.tooltip-label {
    color: var(--text-secondary);
    flex: 1;
    max-width: 200px;
    overflow: hidden;
    text-overflow: ellipsis;
}

.tooltip-value {
    font-weight: 600;
    color: var(--text-primary);
    margin-left: 10px;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--input-bg);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #475569;
}

/* D3 Tooltip */
.tooltip {
    position: absolute;
    text-align: center;
    padding: 8px;
    font: 12px sans-serif;
    background: rgba(0, 0, 0, 0.8);
    color: #fff;
    border-radius: 4px;
    pointer-events: none;
    opacity: 0;
}

.axis text {
    fill: var(--text-secondary);
    font-size: 12px;
}

.axis path,
.axis line {
    stroke: var(--border-color);
}

/* Toggle Switch */
.toggle-switch {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    user-select: none;
}

.toggle-switch input {
    display: none;
}

.toggle-slider {
    position: relative;
    width: 36px;
    height: 20px;
    background-color: var(--border-color);
    border-radius: 10px;
    transition: background-color 0.25s;
}

.toggle-slider::after {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 16px;
    height: 16px;
    background: var(--text-primary);
    border-radius: 50%;
    transition: transform 0.25s;
}

.toggle-switch input:checked+.toggle-slider {
    background-color: var(--accent-color);
}

.toggle-switch input:checked+.toggle-slider::after {
    transform: translateX(16px);
}

.toggle-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 400;
}

/* Export Button */
.export-btn {
    background: transparent;
    border: 1px solid var(--accent-color);
    color: var(--accent-color);
    padding: 0.4rem 1rem;
    border-radius: 8px;
    font-family: var(--font-main);
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.25s ease;
    white-space: nowrap;
}

.export-btn:hover {
    background: var(--accent-color);
    color: var(--bg-color);
    box-shadow: 0 0 15px rgba(56, 189, 248, 0.3);
}

/* PDF Dropdown */
.pdf-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 0.5rem;
    min-width: 300px;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem;
    z-index: 100;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
}

.pdf-dropdown-title {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.pdf-dropdown-list {
    max-height: 200px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.pdf-dropdown-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.4rem 0.5rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.82rem;
    color: var(--text-secondary);
    transition: background 0.15s ease;
}

.pdf-dropdown-item:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}

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

.pdf-dropdown-actions {
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--border-color);
}

.pdf-dropdown-generate {
    width: 100%;
    background: var(--accent-color);
    color: var(--bg-color);
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-family: var(--font-main);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.2s ease;
}

.pdf-dropdown-generate:hover {
    opacity: 0.85;
}

.pdf-dropdown-generate:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}