/* CSS Reset and Variables */
:root {
    --bg-main: #0b0f19;
    --bg-sidebar: rgba(15, 23, 42, 0.7);
    --bg-card: rgba(30, 41, 59, 0.45);
    --bg-card-hover: rgba(30, 41, 59, 0.7);
    --border-color: rgba(51, 65, 85, 0.5);
    --border-active: rgba(99, 102, 241, 0.8);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent: #6366f1;
    --accent-hover: #4f46e5;
    
    /* Neon colors for function curves */
    --color-pink: #ff2a85;
    --color-cyan: #00f0ff;
    --color-green: #39ff14;
    --color-orange: #ff9f00;
    --color-purple: #b026ff;
    
    --shadow-glow: 0 0 15px rgba(99, 102, 241, 0.2);
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
    overflow: hidden;
    height: 100vh;
    width: 100vw;
}

/* App Container Layout */
.app-container {
    display: flex;
    height: 100vh;
    width: 100vw;
    position: relative;
}

/* Sidebar Styling */
.sidebar {
    width: 420px;
    min-width: 380px;
    height: 100%;
    background: var(--bg-sidebar);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    z-index: 10;
    overflow: hidden;
}

.app-header {
    padding: 24px;
    border-bottom: 1px solid var(--border-color);
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--accent), #ec4899);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 16px;
    letter-spacing: -0.5px;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.logo-text h1 {
    font-size: 20px;
    font-weight: 700;
    line-height: 1.2;
}

.logo-text .subtitle {
    font-size: 11px;
    color: var(--text-secondary);
    letter-spacing: 0.5px;
}

/* Sidebar Content Wrapper (Scrollable) */
.sidebar-content {
    flex: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

/* Section Common Styling */
.section {
    padding: 20px 24px;
    display: flex;
    flex-direction: column;
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0; /* Prevent sections from shrinking below content size */
}

.equations-section {
    flex: none;
}

.intersections-section {
    flex: none;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.section-header h2 {
    font-size: 15px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-secondary);
}

/* Custom Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    border-radius: 8px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-fast);
    border: 1px solid transparent;
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    border-color: var(--border-color);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--text-secondary);
}

.btn-sm {
    padding: 6px 12px;
    font-size: 13px;
}

/* Equation List & Card */
.equation-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
    overflow-y: auto;
    padding-right: 4px;
    max-height: 260px; /* Limit height to prevent squeezing other sections */
}

.equation-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--color-pink); /* fallback, dynamic via JS */
    border-radius: 8px;
    padding: 12px 14px;
    transition: var(--transition-normal);
    position: relative;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.equation-card:hover {
    background: var(--bg-card-hover);
    border-color: rgba(255, 255, 255, 0.15);
    box-shadow: 0 4px 20px rgba(0,0,0,0.15);
}

.equation-card.error {
    border-left-color: #ef4444 !important;
}

.equation-row-main {
    display: flex;
    align-items: center;
    gap: 10px;
}

.equation-input-wrap {
    flex: 1;
    position: relative;
}

.equation-input {
    width: 100%;
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 8px 12px;
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 14px;
    transition: var(--transition-fast);
}

.equation-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

.equation-input.error {
    border-color: #ef4444;
}

.equation-input.error:focus {
    box-shadow: 0 0 0 2px rgba(239, 68, 68, 0.2);
}

.eqn-actions {
    display: flex;
    align-items: center;
    gap: 6px;
}

.action-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 6px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
}

.action-btn:hover {
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-primary);
}

.action-btn.delete-btn:hover {
    background: rgba(239, 68, 68, 0.15);
    color: #f87171;
}

.action-btn.active {
    color: var(--accent);
}

.katex-preview {
    font-size: 13px;
    padding-left: 2px;
    min-height: 18px;
    display: flex;
    align-items: center;
    color: var(--text-secondary);
    overflow-x: auto;
    scrollbar-width: none;
}
.katex-preview::-webkit-scrollbar {
    display: none;
}

.error-message {
    color: #f87171;
    font-size: 11px;
    padding-left: 2px;
    margin-top: -4px;
}

/* Intersections Tabs */
.tabs {
    display: flex;
    background: rgba(15, 23, 42, 0.5);
    padding: 3px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    margin-bottom: 12px;
}

.tab-btn {
    flex: 1;
    background: none;
    border: none;
    color: var(--text-secondary);
    padding: 6px 12px;
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    border-radius: 6px;
    transition: var(--transition-fast);
}

.tab-btn:hover {
    color: var(--text-primary);
}

.tab-btn.active {
    background: var(--accent);
    color: var(--text-primary);
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.3);
}

.scrollable {
    overflow-y: auto;
    max-height: 250px; /* Limit height to save space for dynamic parameter card */
    padding-right: 4px;
}

/* Intersection Card */
.intersections-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.intersection-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 10px 14px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: var(--transition-fast);
    cursor: pointer;
}

.intersection-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--accent);
}

.intersection-info {
    display: flex;
    align-items: center;
    gap: 12px;
}

.intersection-indicator {
    display: flex;
    align-items: center;
    position: relative;
    height: 18px;
}

.color-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    box-shadow: 0 0 8px currentColor;
}

.intersection-label {
    display: flex;
    flex-direction: column;
}

.intersection-type {
    font-size: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-muted);
}

.intersection-title {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-primary);
}

.intersection-coords {
    font-family: 'JetBrains Mono', monospace;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-primary);
    background: rgba(15, 23, 42, 0.4);
    padding: 4px 8px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
}

.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--text-muted);
    padding: 40px 20px;
    gap: 8px;
}

.empty-state svg {
    opacity: 0.4;
}

.empty-state p {
    font-size: 13px;
}

/* Sidebar Footer */
.sidebar-footer {
    padding: 16px 24px;
    background: rgba(15, 23, 42, 0.4);
    border-top: 1px solid var(--border-color);
}

.help-toggle {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 13px;
    cursor: pointer;
    transition: var(--transition-fast);
    width: fit-content;
}

.help-toggle:hover {
    color: var(--text-primary);
}

/* Canvas Area */
.canvas-container {
    flex: 1;
    position: relative;
    height: 100%;
    background-color: var(--bg-main);
}

#graph-canvas {
    width: 100%;
    height: 100%;
    display: block;
    cursor: crosshair;
}

/* Canvas HUD Controls overlay */
.canvas-controls {
    position: absolute;
    bottom: 24px;
    right: 24px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    z-index: 5;
}

.hud-btn {
    width: 44px;
    height: 44px;
    background: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-fast);
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}

.hud-btn:hover {
    color: var(--text-primary);
    border-color: var(--accent);
    background: rgba(15, 23, 42, 0.85);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(99, 102, 241, 0.15);
}

.hud-btn:active {
    transform: translateY(0);
}

.hud-btn.active {
    color: var(--accent);
    border-color: var(--accent);
}

/* Mouse Coordinates HUD */
.coords-display {
    position: absolute;
    bottom: 24px;
    left: 24px;
    background: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    padding: 8px 14px;
    border-radius: 8px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 13px;
    color: var(--text-secondary);
    pointer-events: none;
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
    z-index: 5;
}

/* Help Modal overlay */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(11, 15, 25, 0.8);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: auto;
}

.modal {
    background: rgba(30, 41, 59, 0.95);
    border: 1px solid var(--border-color);
    width: 600px;
    max-width: 90vw;
    border-radius: 16px;
    box-shadow: 0 20px 50px rgba(0,0,0,0.5);
    overflow: hidden;
    transform: translateY(20px);
    transition: transform 0.3s ease;
}

.modal-overlay.active .modal {
    transform: translateY(0);
}

.modal-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    font-size: 18px;
    font-weight: 600;
}

.close-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 24px;
    cursor: pointer;
    line-height: 1;
}

.close-btn:hover {
    color: var(--text-primary);
}

.modal-body {
    padding: 24px;
    max-height: 70vh;
    overflow-y: auto;
}

.modal-body p {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.help-table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 20px;
    font-size: 13px;
}

.help-table th, .help-table td {
    padding: 10px 12px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.help-table th {
    color: var(--text-secondary);
    font-weight: 600;
}

.help-table code {
    background: rgba(0,0,0,0.3);
    padding: 3px 6px;
    border-radius: 4px;
    font-family: 'JetBrains Mono', monospace;
    color: var(--accent);
}

.tips-box {
    background: rgba(99, 102, 241, 0.08);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: 8px;
    padding: 16px;
    font-size: 13px;
}

.tips-box strong {
    color: var(--accent);
    display: block;
    margin-bottom: 6px;
}

.tips-box ul {
    padding-left: 18px;
    color: var(--text-secondary);
    display: flex;
    flex-direction: column;
    gap: 4px;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* Responsive adjustments */
@media (max-width: 900px) {
    .app-container {
        flex-direction: column-reverse;
    }
    .sidebar {
        width: 100%;
        height: 50vh;
        border-right: none;
        border-top: 1px solid var(--border-color);
    }
    .canvas-container {
        height: 50vh;
    }
}

/* Parameter Control Section Styling */
.parameter-section {
    flex: none;
}

.param-badge {
    background: rgba(99, 102, 241, 0.15);
    border: 1px solid rgba(99, 102, 241, 0.4);
    color: var(--text-primary);
    padding: 3px 8px;
    border-radius: 6px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    font-weight: 500;
    box-shadow: 0 0 10px rgba(99, 102, 241, 0.1);
}

.parameter-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 14px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.param-row {
    display: flex;
    align-items: center;
    gap: 14px;
}

.btn-play {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--accent);
    color: #ffffff;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
    box-shadow: 0 4px 10px rgba(99, 102, 241, 0.3);
    flex-shrink: 0;
}

.btn-play:hover {
    background: var(--accent-hover);
    transform: scale(1.05);
    box-shadow: 0 6px 14px rgba(99, 102, 241, 0.4);
}

.btn-play:active {
    transform: scale(0.95);
}

.btn-play.playing {
    background: #10b981; /* Green during play */
    box-shadow: 0 0 12px rgba(16, 185, 129, 0.5);
    animation: play-pulse 2s infinite alternate;
}

@keyframes play-pulse {
    0% { box-shadow: 0 0 8px rgba(16, 185, 129, 0.4); }
    100% { box-shadow: 0 0 18px rgba(16, 185, 129, 0.7); }
}

.slider-container {
    flex: 1;
    display: flex;
    align-items: center;
}

/* Custom Slider Styling */
.k-slider {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: #0f172a;
    outline: none;
    -webkit-appearance: none;
    border: 1px solid var(--border-color);
}

.k-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: #ffffff;
    border: 2px solid var(--accent);
    cursor: pointer;
    box-shadow: 0 0 8px rgba(99, 102, 241, 0.8);
    transition: transform var(--transition-fast);
}

.k-slider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.param-config-row {
    display: flex;
    gap: 8px;
}

.config-group {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.config-group label {
    font-size: 10px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.param-num-input {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 6px 8px;
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    text-align: center;
    width: 100%;
    transition: var(--transition-fast);
}

.param-num-input:focus {
    outline: none;
    border-color: var(--accent);
}

.param-option-row {
    margin-top: 4px;
    margin-bottom: 2px;
    display: flex;
    align-items: center;
}

.checkbox-container {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    user-select: none;
}

.checkbox-input {
    appearance: none;
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: rgba(15, 23, 42, 0.6);
    cursor: pointer;
    position: relative;
    transition: var(--transition-fast);
}

.checkbox-input:checked {
    background: var(--accent);
    border-color: var(--accent);
    box-shadow: 0 0 8px rgba(99, 102, 241, 0.5);
}

.checkbox-input:checked::after {
    content: '';
    position: absolute;
    left: 4px;
    top: 1px;
    width: 4px;
    height: 7px;
    border: solid #ffffff;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.checkbox-label {
    font-size: 12px;
    color: var(--text-secondary);
    transition: var(--transition-fast);
}

.checkbox-container:hover .checkbox-label {
    color: var(--text-primary);
}

.checkbox-container:hover .checkbox-input {
    border-color: var(--text-secondary);
}

/* Toast Notification Styling */
.toast-notification {
    position: absolute;
    top: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(-20px);
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid #10b981;
    border-radius: 8px;
    padding: 10px 18px;
    color: #ffffff;
    font-size: 13px;
    font-weight: 500;
    pointer-events: none;
    z-index: 1000;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5), 0 0 15px rgba(16, 185, 129, 0.2);
    transition: all 0.35s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    display: flex;
    align-items: center;
    gap: 8px;
    opacity: 0;
}

.toast-notification.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

.hidden {
    display: none !important;
}

/* Tooltip Styling */
.tooltip {
    position: absolute;
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    padding: 8px 12px;
    border-radius: 8px;
    font-size: 12px;
    color: var(--text-primary);
    pointer-events: none;
    z-index: 100;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.4);
    transition: opacity var(--transition-fast), transform 0.05s linear;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.tooltip-title {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.tooltip-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 13px;
    color: var(--text-primary);
}

.tooltip-coords {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    color: var(--accent);
}