:root {
    --bg-dark: #0F1115;
    --bg-sidebar: #161921;
    --text-primary: #FFFFFF;
    --text-secondary: #94A3B8;
    --border-color: #2E3342;
    --accent: #6C63FF;

    --color-margin: rgba(249, 204, 157, 0.7);
    --color-margin-solid: #F9CC9D;
    --color-border: rgba(253, 224, 152, 0.7);
    --color-border-solid: #FDE098;
    --color-padding: rgba(195, 208, 139, 0.7);
    --color-padding-solid: #C3D08B;
    --color-content: rgba(140, 179, 217, 0.7);
    --color-content-solid: #8CB3D9;
}

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

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

.app-container {
    display: flex;
    width: 100%;
    height: 100%;
}

/* Sidebar */
.sidebar {
    width: 340px;
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    padding: 2rem;
    overflow-y: auto;
    z-index: 10;
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.5);
}

.sidebar header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(90deg, #fff, #a5b4fc);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.sidebar header p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    line-height: 1.5;
    margin-bottom: 2rem;
}

.controls {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.control-box {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.05);
    padding: 1rem;
    border-radius: 8px;
}

.control-box>label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.margin-control>label {
    color: var(--color-margin-solid);
}

.border-control>label {
    color: var(--color-border-solid);
}

.padding-control>label {
    color: var(--color-padding-solid);
}

.toggle-container {
    display: flex;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 6px;
    padding: 4px;
    margin-bottom: 0.5rem;
}

.toggle-btn {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 0.5rem;
    font-size: 0.85rem;
    font-weight: 600;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s;
}

.toggle-btn.active {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.sizing-desc {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-style: italic;
}

.slider-group {
    margin-bottom: 0.5rem;
}

.slider-group:last-child {
    margin-bottom: 0;
}

.slider-group span {
    display: flex;
    justify-content: space-between;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.slider-group .val {
    color: var(--text-primary);
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 4px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 2px;
    outline: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--text-primary);
    cursor: pointer;
    transition: transform 0.1s;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

/* Main Content - 3D */
.main-content {
    flex: 1;
    position: relative;
    perspective: 1200px;
    overflow: hidden;
    cursor: grab;
    background: radial-gradient(circle at center, #1E2235 0%, #0F1115 100%);
}

.main-content:active {
    cursor: grabbing;
}

.scene {
    width: 100%;
    height: 100%;
    position: absolute;
    transform-style: preserve-3d;
    transform: rotateX(55deg) rotateZ(35deg);
    transform-origin: center center;
    transition: transform 0.1s ease-out;
    /* For dragging */
}

/* Base plane style */
.plane {
    position: absolute;
    top: 50%;
    left: 50%;
    transform-style: preserve-3d;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px dashed rgba(255, 255, 255, 0.2);
    transition: all 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
}

.plane .label {
    position: absolute;
    top: 8px;
    left: 8px;
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    color: rgba(0, 0, 0, 0.8);
    letter-spacing: 0.05em;
    background: rgba(255, 255, 255, 0.3);
    padding: 2px 6px;
    border-radius: 4px;
}

.plane .dimensions {
    font-family: monospace;
    font-size: 1rem;
    font-weight: 600;
    color: rgba(0, 0, 0, 0.9);
    background: rgba(255, 255, 255, 0.5);
    padding: 4px 8px;
    border-radius: 4px;
}

/* Specific planes */
.plane-margin {
    background-color: var(--color-margin);
    border-color: var(--color-margin-solid);
}

.plane-border {
    background-color: var(--color-border);
    border-color: var(--color-border-solid);
}

.plane-padding {
    background-color: var(--color-padding);
    border-color: var(--color-padding-solid);
}

.plane-content {
    background-color: var(--color-content);
    border-color: var(--color-content-solid);
}

/* Math Tooltip */
.math-tooltip {
    position: absolute;
    top: 2rem;
    right: 2rem;
    background: rgba(22, 25, 33, 0.9);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    border-radius: 12px;
    width: 300px;
    pointer-events: none;
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.5);
}

.math-tooltip h3 {
    font-size: 1rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.math-tooltip hr {
    border: none;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin: 1rem 0;
}

.math-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-size: 0.85rem;
}

.math-row span {
    color: var(--text-secondary);
}

.math-row strong {
    color: var(--text-primary);
    font-size: 0.95rem;
}

.math-formula {
    font-family: monospace;
    font-size: 0.75rem;
    color: var(--accent);
    background: rgba(108, 99, 255, 0.1);
    padding: 0.5rem;
    border-radius: 6px;
    line-height: 1.4;
}

.drag-hint {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    color: rgba(255, 255, 255, 0.4);
    font-size: 0.85rem;
    letter-spacing: 0.05em;
    pointer-events: none;
}