:root {
    /* Perspective Triad Theme */
    --app-bg: #fdfbf7;
    --panel-bg: rgba(255, 255, 255, 0.6);
    --glass-border: rgba(139, 0, 0, 0.1);
    --text-primary: #2c2c2c;
    --text-secondary: #5a5a5a;

    --accent-red: #d63b1d;
    --accent-gold: #c5a059;
    --accent-blue: #007aff;
    --accent-green: #27c93f;

    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);

    --font-family: "Noto Serif SC", "Outfit", serif;
    --font-mono: "JetBrains Mono", monospace;
    --font-title: "Ma Shan Zheng", cursive;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--app-bg);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    background-image: url('https://images.unsplash.com/photo-1493612276216-9c5901955d43?q=80&w=2672&auto=format&fit=crop');
    /* Abstract Triad/Geometry */
    background-size: cover;
    background-position: center;
}

.app-container {
    width: 95vw;
    height: 90vh;
    max-width: 1600px;
    background: rgba(255, 252, 245, 0.92);
    backdrop-filter: blur(20px);
    border-radius: 24px;
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* Header */
.main-header {
    padding: 1.5rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--glass-border);
    background: rgba(255, 255, 255, 0.5);
}

.header-content h1 {
    font-family: var(--font-title);
    font-size: 2rem;
    font-weight: 400;
    color: var(--accent-red);
}

.subtitle {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-style: italic;
    margin-top: -5px;
}

.header-controls {
    display: flex;
    gap: 10px;
}

.apple-btn {
    padding: 8px 16px;
    background: #fff;
    border: 1px solid rgba(0, 0, 0, 0.1);
    border-radius: 8px;
    font-family: var(--font-family);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.85rem;
}

.apple-btn:hover {
    background: #f5f5f5;
    border-color: var(--accent-gold);
    transform: translateY(-1px);
}

/* Main Stage - Triad */
.triad-stage {
    flex-grow: 1;
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 20px;
    padding: 20px;
    overflow: hidden;
}

.perspective-panel {
    background: var(--panel-bg);
    border-radius: 16px;
    border: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: all 0.3s ease;
}

.perspective-panel:hover {
    box-shadow: var(--shadow-md);
    background: rgba(255, 255, 255, 0.8);
}

.panel-header {
    padding: 16px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    text-align: center;
    background: rgba(255, 255, 255, 0.3);
}

.panel-icon {
    font-size: 2rem;
    margin-bottom: 8px;
}

.panel-header h3 {
    font-size: 1.2rem;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.panel-sub {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-family: var(--font-mono);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.panel-content {
    flex-grow: 1;
    padding: 20px;
    overflow-y: auto;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

/* Set View */
.set-panel {
    border-top: 4px solid var(--accent-blue);
}

.set-container {
    display: flex;
    align-items: flex-start;
    font-family: var(--font-mono);
    font-size: 1.2rem;
    color: var(--text-primary);
    width: 100%;
    height: 100%;
}

.set-bracket {
    font-size: 3rem;
    font-weight: 300;
    color: var(--text-secondary);
    line-height: 1;
}

.set-list {
    flex-grow: 1;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    padding: 10px;
    align-content: flex-start;
    overflow-y: auto;
    max-height: 100%;
}

.set-pair {
    background: #fff;
    padding: 4px 8px;
    border-radius: 6px;
    border: 1px solid rgba(0, 0, 0, 0.1);
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: 6px;
}

.set-pair:hover {
    background: #f0f8ff;
    border-color: var(--accent-blue);
    transform: scale(1.05);
}

.set-pair.active {
    background: var(--accent-blue);
    color: white;
    border-color: var(--accent-blue);
}

.pair-remove {
    font-size: 0.8rem;
    opacity: 0.5;
    margin-left: 4px;
}

.pair-remove:hover {
    opacity: 1;
    color: var(--accent-red);
}

.empty-state {
    color: #ccc;
    font-style: italic;
    width: 100%;
    text-align: center;
    margin-top: 20px;
}

/* Matrix View */
.matrix-panel {
    border-top: 4px solid var(--accent-green);
}

.matrix-wrapper {
    display: grid;
    gap: 4px;
    background: #f0f0f0;
    padding: 10px;
    border-radius: 8px;
}

.matrix-cell {
    width: 40px;
    height: 40px;
    background: #fff;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: var(--font-mono);
    font-size: 1rem;
    color: #ccc;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s;
}

.matrix-cell:hover {
    background: #e0e0e0;
}

.matrix-cell.active {
    background: var(--accent-green);
    color: white;
    font-weight: 700;
    box-shadow: 0 2px 8px rgba(39, 201, 63, 0.3);
}

.matrix-header-cell {
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* Graph View */
.graph-panel {
    border-top: 4px solid var(--accent-red);
}

.graph-content {
    padding: 0;
}

.graph-svg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 5;
}

.nodes-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10;
    pointer-events: none;
}

.graph-node {
    position: absolute;
    width: 40px;
    height: 40px;
    background: #fff;
    border: 2px solid var(--accent-red);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: var(--font-title);
    font-size: 1.2rem;
    color: var(--accent-red);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    pointer-events: auto;
    cursor: pointer;
    transition: all 0.3s;
    z-index: 20;
}

.graph-node:hover {
    transform: scale(1.1);
    background: var(--accent-red);
    color: white;
}

.graph-edge {
    stroke: var(--accent-red);
    stroke-width: 2;
    fill: none;
    marker-end: url(#arrowhead);
    cursor: pointer;
    pointer-events: auto;
    transition: all 0.3s;
}

.graph-edge:hover {
    stroke-width: 4;
    stroke: var(--accent-gold);
    marker-end: url(#arrowhead-loop);
}

.graph-edge.loop {
    marker-end: url(#arrowhead-loop);
    stroke: var(--accent-gold);
}

/* Ghost edge for interaction */
.ghost-edge {
    stroke: rgba(0, 0, 0, 0.05);
    stroke-width: 10;
    fill: none;
    cursor: pointer;
    pointer-events: auto;
}

.ghost-edge:hover {
    stroke: rgba(214, 59, 29, 0.2);
}

/* Footer */
.insight-footer {
    padding: 1rem 2rem;
    background: #fff;
    border-top: 1px solid var(--glass-border);
    display: flex;
    align-items: center;
    gap: 12px;
}

.insight-icon {
    font-size: 1.5rem;
}

.insight-footer p {
    font-size: 0.95rem;
    color: var(--text-secondary);
}