:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --accent-primary: #f59e0b; /* Amber for Sparse Matrix */
    --accent-secondary: #38bdf8;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border-color: rgba(255, 255, 255, 0.1);
    --triplet-bg: #1e293b;
    --triplet-highlight: rgba(245, 158, 11, 0.2);
    --triplet-active: #f59e0b;
}

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

body {
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: 'Inter', sans-serif;
    overflow: hidden;
    height: 100vh;
}

.top-nav {
    height: 60px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 2rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
}

.nav-brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent-primary);
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
}

.simulator-container {
    display: grid;
    grid-template-columns: 280px 1fr 350px;
    height: calc(100vh - 60px);
}

/* Sidebar */
.sidebar {
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.sidebar-header { padding: 1.5rem; }
.sidebar-header h2 { font-size: 0.8rem; color: var(--text-secondary); text-transform: uppercase; }

.algo-nav { padding: 0 0.75rem; }
.algo-nav .nav-link {
    display: block;
    padding: 0.75rem 1rem;
    border-radius: 8px;
    margin-bottom: 0.25rem;
    transition: all 0.2s;
}

.algo-nav .nav-link.active {
    background: rgba(245, 158, 11, 0.1);
    color: var(--accent-primary);
}

.controls-panel {
    margin-top: auto;
    padding: 1.5rem;
    border-top: 1px solid var(--border-color);
}

.secondary-btn {
    width: 100%;
    padding: 0.6rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-primary);
    font-size: 0.85rem;
    cursor: pointer;
    margin-bottom: 0.5rem;
}

.main-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    margin-top: 1rem;
}

.play-btn {
    width: 45px; height: 45px; border-radius: 50%;
    background: var(--accent-primary); border: none;
    display: flex; justify-content: center; align-items: center;
    cursor: pointer;
}

/* Visualizer Area */
.visualizer-area {
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    background: #0c1220;
}

.workspace {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: space-around;
    gap: 1rem;
}

.matrix-container {
    flex: 1;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.matrix-container h3 {
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    margin-bottom: 1rem;
    text-align: center;
}

.triplet-view {
    flex: 1;
    background: var(--bg-secondary);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    overflow-y: auto;
    padding: 0.5rem;
}

.op-indicator {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-secondary);
}

.status-panel {
    margin-top: 1.5rem;
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 1rem;
    border: 1px solid var(--border-color);
}

.status-header {
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
}

.status-content { font-size: 0.9rem; line-height: 1.4; }

/* Triplet Rows */
.triplet-row {
    display: grid;
    grid-template-columns: 1fr 1fr 1.5fr;
    gap: 0.5rem;
    padding: 0.5rem;
    margin-bottom: 0.25rem;
    border-radius: 6px;
    background: rgba(255, 255, 255, 0.03);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    transition: all 0.2s;
}

.triplet-row.header {
    background: none;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-weight: 700;
}

.triplet-row.active {
    background: var(--triplet-highlight);
    border: 1px solid var(--triplet-active);
}

.val-box { text-align: center; }

/* Explanation Side */
.explanation-side {
    background: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.code-block {
    background: #0f172a;
    padding: 1rem;
    border-radius: 8px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    line-height: 1.5;
    overflow-x: auto;
}

.triplet-list {
    flex: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.calculation-log {
    padding: 0.75rem;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 6px;
    font-size: 0.85rem;
    border-left: 3px solid var(--accent-primary);
    animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateX(10px); }
    to { opacity: 1; transform: translateX(0); }
}

.lang-select { background: #0f172a; color: white; border: 1px solid var(--border-color); font-size: 0.75rem; }
input[type="range"] { width: 100%; accent-color: var(--accent-primary); }