:root {
    --primary: #10b981;
    --primary-dark: #059669;
    --secondary: #3b82f6;
    --accent: #8b5cf6;
    --bg-dark: #0f172a;
    --card-bg: rgba(255, 255, 255, 0.8);
    --glass-bg: rgba(255, 255, 255, 0.1);
    --glass-border: rgba(255, 255, 255, 0.2);
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
}

#phet-stage {
    position: absolute;
    top: 0;
    left: 0;
    width: 1280px;
    height: 720px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background: #0f172a;
    transform-origin: top left;
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Outfit', sans-serif;
    color: var(--text-main);
    overflow: hidden;
}

nav {
    position: relative !important;
}
.lab-header {
    text-align: center;
    padding: 15px 5% 10px;
}

.mode-selector {
    display: flex;
    justify-content: center;
    gap: 0.8rem;
    padding: 10px;
    background: #f1f5f9;
    width: fit-content;
    margin: 0 auto;
    border-radius: 100px;
    border: 1px solid #e2e8f0;
}

.mode-btn {
    padding: 0.6rem 1.2rem;
    border: none;
    background: transparent;
    border-radius: 100px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    color: var(--text-muted);
    font-size: 0.9rem;
    white-space: nowrap;
}

.mode-btn.active {
    background: white;
    color: var(--primary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

@media (max-width: 768px) {
    .lab-header {
        padding: 15px 0;
        margin-top: 70px;
    }

    .mode-selector {
        width: 100%;
        border-radius: 0;
        background: transparent;
        border: none;
        overflow-x: auto;
        justify-content: flex-start;
        padding: 10px 20px;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
    }

    .mode-selector::-webkit-scrollbar {
        display: none;
    }

    .mode-btn {
        background: #fff;
        border: 1px solid #e2e8f0;
        padding: 0.6rem 1.2rem;
        flex-shrink: 0;
        font-size: 0.85rem;
    }

    .mode-btn.active {
        background: var(--primary);
        color: white;
        border-color: var(--primary);
        box-shadow: 0 4px 10px rgba(16, 185, 129, 0.2);
    }
}

.sim-container {
    display: grid;
    grid-template-columns: 1fr 340px;
    gap: 1.5rem;
    padding: 0 20px 20px;
    flex: 1;
    min-height: 0;
    overflow: hidden;
    max-width: none;
}

.canvas-wrapper {
    flex: 2;
    /* Larger canvas */
    position: relative;
    background: #000;
    border-radius: clamp(16px, 3vw, 24px);
    overflow: hidden;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.1);
}

#three-container {
    width: 100%;
    height: 100%;
}

/* Overlays Scaling */
.hud-overlay {
    position: absolute;
    top: clamp(10px, 2vw, 20px);
    right: clamp(10px, 2vw, 20px);
    display: flex;
    flex-direction: column;
    gap: 8px;
    pointer-events: none;
    z-index: 5;
}

.hud-item {
    background: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(8px);
    padding: 8px 12px;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: white;
    min-width: 120px;
}

.hud-label {
    display: block;
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: #94a3b8;
}

.hud-value {
    display: block;
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    font-weight: 700;
    font-family: 'Space Grotesk', sans-serif;
}

.law-desc {
    position: absolute;
    bottom: clamp(10px, 2vw, 20px);
    left: clamp(10px, 2vw, 20px);
    right: clamp(10px, 2vw, 20px);
    background: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(12px);
    padding: clamp(15px, 2vw, 25px);
    border-radius: 16px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: white;
    max-width: 450px;
    pointer-events: none;
}

.law-desc h3 {
    margin: 0 0 5px;
    font-size: 1.1rem;
    color: var(--primary);
}

.law-desc p {
    margin: 0;
    font-size: 0.85rem;
    line-height: 1.4;
    opacity: 0.9;
}

/* Controls Scaling */
.controls-wrapper {
    flex: 1;
    min-width: 0;
    background: rgba(15, 23, 42, 0.6);
    padding: 20px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    display: flex;
    flex-direction: column;
    gap: 1rem;
    border: 1.5px solid rgba(255, 255, 255, 0.1);
    overflow-y: auto;
    color: #fff;
    backdrop-filter: blur(10px);
}
.controls-wrapper::-webkit-scrollbar { width: 4px; }
.controls-wrapper::-webkit-scrollbar-thumb { background: rgba(59, 130, 246, 0.3); border-radius: 10px; }

.controls-wrapper h3 {
    margin: 0;
    font-size: 1.2rem;
    padding-bottom: 10px;
    border-bottom: 2px solid #f1f5f9;
}

.control-panel {
    display: none;
    flex-direction: column;
    gap: 1.5rem;
}

.control-panel.active {
    display: flex;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.control-group label {
    font-weight: 600;
    font-size: 0.85rem;
    display: flex;
    justify-content: space-between;
}

.control-group label span {
    color: var(--primary);
}

input[type="range"] {
    width: 100%;
    accent-color: var(--primary);
    cursor: pointer;
}

.toggle-group {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #f8fafc;
    padding: 10px 15px;
    border-radius: 12px;
}

.push-btn {
    padding: 0.8rem;
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    border: none;
    border-radius: 10px;
}