:root {
    --bg-dark: #0F172A;
    --bg-card: rgba(30, 41, 59, 0.7);
    --primary: #F59E0B;
    --primary-hover: #D97706;
    --accent: #EF4444;
    --accent-hover: #DC2626;
    --text-main: #F8FAFC;
    --text-muted: #94A3B8;
    --border-color: rgba(248, 250, 252, 0.1);
    
    --accept-color: #10B981;
    --reject-color: #EF4444;
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    line-height: 1.5;
    min-height: 100vh;
    overflow-x: hidden;
}

.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* Header & Controls */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--primary);
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-main);
}

.global-controls {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.control-group label {
    font-size: 0.875rem;
    color: var(--text-muted);
}

input[type="range"] {
    accent-color: var(--primary);
    width: 150px;
}

/* Base Inputs */
select, input[type="number"] {
    background-color: rgba(15, 23, 42, 0.5);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    padding: 0.5rem;
    border-radius: 6px;
    font-family: 'Inter', sans-serif;
    font-size: 0.9rem;
    outline: none;
    transition: border-color 0.2s;
}

select:focus, input[type="number"]:focus {
    border-color: var(--primary);
}

/* Buttons */
.btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    font-weight: 500;
    font-size: 0.875rem;
    cursor: pointer;
    border: none;
    transition: all 0.2s ease;
    font-family: 'Inter', sans-serif;
}

.btn.primary {
    background-color: var(--primary);
    color: #fff;
}

.btn.primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.btn.secondary {
    background-color: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-main);
}

.btn.secondary:hover {
    background-color: rgba(248, 250, 252, 0.05);
}

/* Main Sandbox Area */
.sandbox-area {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.algo-panel {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 1rem;
    border-bottom: 1px solid rgba(248, 250, 252, 0.05);
}

.panel-header h2 {
    font-size: 1.125rem;
    font-weight: 600;
}

.algo-select {
    font-size: 1rem;
    font-weight: 500;
    min-width: 180px;
}

.panel-controls {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: 1rem;
}

/* Visualization Area */
.visualizer-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 8px;
    padding: 1.5rem;
    align-items: center;
}

.visualizer {
    position: relative;
    width: 300px;
    height: 200px;
}

.metrics {
    display: flex;
    width: 100%;
    justify-content: space-around;
    border-top: 1px solid var(--border-color);
    padding-top: 1rem;
}

.metric-card {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.metric-value {
    font-size: 1.5rem;
    font-weight: 700;
}

.metric-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.accept-text { color: var(--accept-color); }
.reject-text { color: var(--reject-color); }

/* Timeline */
.timeline-container h3 {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.timeline-track {
    height: 32px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 16px;
    position: relative;
    overflow: hidden;
    display: flex;
    align-items: center;
}

.timeline-dot {
    position: absolute;
    width: 6px;
    height: 16px;
    border-radius: 3px;
    /* animation added in JS */
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.modal:not(.hidden) {
    opacity: 1;
    pointer-events: all;
}

.modal-content {
    background: var(--bg-dark);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    width: 600px;
    max-width: 90vw;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.5);
    transform: translateY(20px);
    transition: transform 0.3s ease;
}

.modal:not(.hidden) .modal-content {
    transform: translateY(0);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.btn-icon {
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    transition: color 0.2s;
}

.btn-icon:hover {
    color: var(--text-main);
}

.modal-tabs {
    display: flex;
    gap: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.tab-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 0.5rem 1rem;
    cursor: pointer;
    font-family: inherit;
    font-weight: 500;
    border-bottom: 2px solid transparent;
    margin-bottom: -1px;
}

.tab-btn.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
}

pre {
    background: rgba(0, 0, 0, 0.3);
    padding: 1rem;
    border-radius: 6px;
    overflow-x: auto;
    font-size: 0.875rem;
    color: #e2e8f0;
}

/* Responsive */
@media (max-width: 800px) {
    .sandbox-area {
        grid-template-columns: 1fr;
    }
    
    .app-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .global-controls {
        width: 100%;
        flex-wrap: wrap;
    }
}