:root {
    /* Livelihood Green & Warm Red Theme */
    --app-bg: #fdfbf7;
    --panel-bg: rgba(255, 255, 255, 0.9);
    --glass-border: rgba(0, 0, 0, 0.08);
    --text-primary: #2d3436;
    --text-secondary: #636e72;

    --domain-color: #0984e3;
    /* Blue for People */
    --codomain-color: #00b894;
    /* Green for Well-being */
    --mapping-color: #d63031;
    /* Red for Policy */

    --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 10px 20px 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-1532629345422-7515f3d16bb6?q=80&w=2670&auto=format&fit=crop');
    background-size: cover;
    background-position: center;
}

.app-container {
    width: 95vw;
    height: 90vh;
    max-width: 1600px;
    background: rgba(255, 252, 245, 0.96);
    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: 1.2rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--glass-border);
    background: rgba(255, 255, 255, 0.6);
}

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

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

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

.header-controls {
    display: flex;
    gap: 16px;
    align-items: center;
}

.mode-toggle {
    display: flex;
    background: #fff;
    padding: 4px;
    border-radius: 12px;
    border: 1px solid rgba(0, 0, 0, 0.08);
}

.toggle-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    border: none;
    background: transparent;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    opacity: 0.7;
    font-family: var(--font-family);
    font-weight: 600;
}

.toggle-btn:hover {
    opacity: 1;
    background: rgba(0, 0, 0, 0.02);
}

.toggle-btn.active {
    opacity: 1;
    background: var(--mapping-color);
    color: white;
    box-shadow: 0 2px 8px rgba(214, 48, 49, 0.3);
}

.apple-btn {
    padding: 10px;
    border-radius: 10px;
    border: 1px solid rgba(0, 0, 0, 0.1);
    background: #fff;
    cursor: pointer;
    transition: all 0.2s;
    color: var(--text-secondary);
}

.apple-btn:hover {
    background: #f5f5f5;
    transform: scale(1.05);
}

/* Main Stage */
.main-stage {
    flex-grow: 1;
    display: grid;
    grid-template-columns: 300px 1fr 300px 320px;
    gap: 2px;
    background: rgba(0, 0, 0, 0.02);
    overflow: hidden;
}

.set-panel {
    background: var(--panel-bg);
    display: flex;
    flex-direction: column;
    padding: 20px;
    border-right: 1px solid var(--glass-border);
    position: relative;
}

.domain-panel {
    border-left: 1px solid var(--glass-border);
}

.codomain-panel {
    border-right: 1px solid var(--glass-border);
}

.panel-header {
    margin-bottom: 20px;
    text-align: center;
}

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

.math-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-family: var(--font-mono);
}

.elements-container {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    gap: 12px;
    overflow-y: auto;
    padding: 4px;
}

.selection-count {
    text-align: center;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 10px;
    padding-top: 10px;
    border-top: 1px dashed rgba(0, 0, 0, 0.1);
}

/* Elements */
.element-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: #fff;
    border-radius: 12px;
    border: 1px solid rgba(0, 0, 0, 0.05);
    cursor: pointer;
    transition: all 0.2s;
    position: relative;
}

.element-item:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-sm);
}

.domain-panel .element-item.selected {
    border-color: var(--domain-color);
    background: rgba(9, 132, 227, 0.05);
}

.codomain-panel .element-item.selected {
    border-color: var(--codomain-color);
    background: rgba(0, 184, 148, 0.05);
}

.codomain-panel .element-item.highlighted {
    border-color: var(--mapping-color);
    background: rgba(214, 48, 49, 0.05);
    box-shadow: 0 0 8px rgba(214, 48, 49, 0.2);
}

.elem-icon {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: #f5f6fa;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.elem-info h4 {
    font-size: 0.95rem;
    margin-bottom: 2px;
}

.elem-info p {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* Mapping Area */
.mapping-area {
    position: relative;
    background: rgba(255, 255, 255, 0.4);
    overflow: hidden;
}

.mapping-svg {
    width: 100%;
    height: 100%;
}

.function-label {
    position: absolute;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: #fff;
    padding: 6px 16px;
    border-radius: 20px;
    box-shadow: var(--shadow-sm);
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    color: var(--mapping-color);
    font-weight: 600;
}

.mapping-path {
    fill: none;
    stroke: #ccc;
    stroke-width: 1.5px;
    opacity: 0.2;
    transition: all 0.4s ease;
    marker-end: url(#arrow-default);
}

.mapping-path.active {
    stroke: var(--mapping-color);
    stroke-width: 3px;
    opacity: 0.8;
    marker-end: url(#arrow-active);
    filter: drop-shadow(0 2px 4px rgba(214, 48, 49, 0.2));
}

/* Insight Panel */
.insight-panel {
    background: var(--panel-bg);
    padding: 24px;
    gap: 20px;
    display: flex;
    flex-direction: column;
    border-left: 1px solid var(--glass-border);
}

.concept-card,
.insight-card {
    background: #fff;
    border-radius: 16px;
    padding: 20px;
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.concept-card {
    border-top: 4px solid var(--mapping-color);
}

.card-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
}

.card-icon {
    font-size: 1.6rem;
}

.card-header h4 {
    font-size: 1.1rem;
    color: var(--text-primary);
}

.card-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 16px;
}

.math-box {
    background: rgba(0, 0, 0, 0.03);
    padding: 12px;
    border-radius: 8px;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--text-primary);
    text-align: center;
    border: 1px dashed rgba(0, 0, 0, 0.2);
}

/* Insight */
.insight-card {
    background: linear-gradient(135deg, #fff5f5 0%, #fff 100%);
    border: 1px solid rgba(214, 48, 49, 0.2);
}

.insight-card h4 {
    color: var(--mapping-color);
    margin-bottom: 10px;
    font-size: 1rem;
}

.insight-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}