:root {
        --geo-primary: #3B82F6;
        --geo-secondary: #8B5CF6;
        --geo-success: #10B981;
        --geo-warning: #F59E0B;
        --geo-dark: var(--gray-900);
        --geo-light: var(--gray-100);
    }

    .geo-page {
        min-height: calc(100vh - 200px);
        padding: 1.5rem 0;
        background: linear-gradient(180deg, var(--gray-50) 0%, var(--gray-50) 100%);
    }

    .geo-container {
        max-width: 1400px;
        margin: 0 auto;
        padding: 0 1rem;
    }

    /* Header */
    .geo-header {
        text-align: center;
        margin-bottom: 1.5rem;
    }

    .geo-title {
        font-size: clamp(1.5rem, 4vw, 2.25rem);
        font-weight: 900;
        background: linear-gradient(135deg, var(--geo-primary), var(--geo-secondary));
        -webkit-background-clip: text;
        -webkit-text-fill-color: transparent;
        background-clip: text;
        margin-bottom: 0.5rem;
    }

    .geo-subtitle {
        color: var(--gray-500);
        font-size: 1rem;
    }

    /* Main Layout */
    .geo-main {
        display: grid;
        grid-template-columns: 280px 1fr 300px;
        gap: 1.5rem;
        align-items: start;
    }

    @media (max-width: 1200px) {
        .geo-main {
            grid-template-columns: 1fr;
        }
    }

    /* Tools Panel */
    .geo-tools {
        background: var(--white);
        border-radius: 16px;
        padding: 1.25rem;
        box-shadow: 0 4px 20px rgba(0,0,0,0.06);
    }

    .geo-tools h3 {
        font-size: 0.95rem;
        font-weight: 700;
        color: var(--geo-dark);
        margin-bottom: 1rem;
        display: flex;
        align-items: center;
        gap: 0.5rem;
    }

    .tool-grid {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }

    .tool-btn {
        padding: 0.875rem 0.75rem;
        border: 2px solid var(--geo-light);
        border-radius: 12px;
        background: var(--white);
        cursor: pointer;
        transition: all 0.2s;
        display: flex;
        flex-direction: column;
        align-items: center;
        gap: 0.5rem;
        font-size: 0.8rem;
        font-weight: 600;
        color: var(--gray-500);
    }

    .tool-btn:hover {
        border-color: var(--geo-primary);
        color: var(--geo-primary);
    }

    .tool-btn.active {
        border-color: var(--geo-primary);
        background: rgba(59, 130, 246, 0.1);
        color: var(--geo-primary);
    }

    .tool-btn i {
        font-size: 1.5rem;
    }

    /* Canvas Area */
    .geo-canvas-area {
        background: var(--white);
        border-radius: 16px;
        box-shadow: 0 4px 20px rgba(0,0,0,0.06);
        overflow: hidden;
    }

    .canvas-toolbar {
        display: flex;
        justify-content: space-between;
        align-items: center;
        padding: 0.75rem 1rem;
        background: var(--geo-light);
        border-bottom: 1px solid var(--gray-200);
    }

    .canvas-toolbar-left {
        display: flex;
        gap: 0.5rem;
    }

    .canvas-toolbar-btn {
        padding: 0.5rem 0.75rem;
        border: none;
        border-radius: 8px;
        background: var(--white);
        cursor: pointer;
        font-size: 0.85rem;
        font-weight: 600;
        color: var(--gray-500);
        display: flex;
        align-items: center;
        gap: 0.4rem;
        transition: all 0.2s;
    }

    .canvas-toolbar-btn:hover {
        background: var(--geo-primary);
        color: white;
    }

    .canvas-wrapper {
        position: relative;
        width: 100%;
        height: 500px;
        background: var(--white);
        background-image:
            linear-gradient(rgba(59, 130, 246, 0.08) 1px, transparent 1px),
            linear-gradient(90deg, rgba(59, 130, 246, 0.08) 1px, transparent 1px);
        background-size: 20px 20px;
        cursor: crosshair;
    }

    #geoCanvas {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
    }

    /* Instructions Panel */
    .geo-instructions {
        background: var(--white);
        border-radius: 16px;
        padding: 1.25rem;
        box-shadow: 0 4px 20px rgba(0,0,0,0.06);
    }

    .geo-instructions h3 {
        font-size: 0.95rem;
        font-weight: 700;
        color: var(--geo-dark);
        margin-bottom: 1rem;
    }

    .construction-select {
        width: 100%;
        padding: 0.75rem;
        border: 2px solid var(--geo-light);
        border-radius: 10px;
        font-size: 0.9rem;
        font-weight: 600;
        margin-bottom: 1rem;
        cursor: pointer;
    }

    .construction-select:focus {
        outline: 2px solid transparent;
        border-color: var(--geo-primary);
    }

    /* Steps */
    .step-list {
        display: flex;
        flex-direction: column;
        gap: 0.75rem;
    }

    .step-item {
        padding: 0.875rem;
        border-radius: 10px;
        border: 2px solid var(--geo-light);
        transition: all 0.2s;
    }

    .step-item.current {
        border-color: var(--geo-primary);
        background: rgba(59, 130, 246, 0.05);
    }

    .step-item.completed {
        border-color: var(--geo-success);
        background: rgba(16, 185, 129, 0.05);
    }

    .step-item.locked {
        opacity: 0.5;
    }

    .step-header {
        display: flex;
        align-items: center;
        gap: 0.75rem;
        margin-bottom: 0.5rem;
    }

    .step-number {
        width: 24px;
        height: 24px;
        border-radius: 50%;
        background: var(--geo-primary);
        color: white;
        font-size: 0.75rem;
        font-weight: 700;
        display: flex;
        align-items: center;
        justify-content: center;
        flex-shrink: 0;
    }

    .step-item.completed .step-number {
        background: var(--geo-success);
    }

    .step-tool {
        display: inline-flex;
        align-items: center;
        gap: 0.25rem;
        padding: 0.2rem 0.5rem;
        background: var(--geo-light);
        border-radius: 4px;
        font-size: 0.7rem;
        font-weight: 600;
        color: var(--gray-500);
    }

    .step-instruction {
        font-size: 0.85rem;
        color: var(--geo-dark);
        line-height: 1.5;
    }

    /* Progress */
    .progress-bar {
        height: 6px;
        background: var(--geo-light);
        border-radius: 3px;
        margin-top: 1rem;
        overflow: hidden;
    }

    .progress-fill {
        height: 100%;
        background: linear-gradient(90deg, var(--geo-primary), var(--geo-secondary));
        border-radius: 3px;
        transition: width 0.3s;
    }

    /* Buttons */
    .geo-btn {
        width: 100%;
        padding: 0.875rem;
        border: none;
        border-radius: 10px;
        font-size: 0.95rem;
        font-weight: 700;
        cursor: pointer;
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 0.5rem;
        transition: all 0.2s;
        margin-top: 1rem;
    }

    .geo-btn-primary {
        background: linear-gradient(135deg, var(--geo-primary), var(--geo-secondary));
        color: white;
    }

    .geo-btn-primary:hover {
        transform: translateY(-2px);
        box-shadow: 0 6px 20px rgba(59, 130, 246, 0.3);
    }

    .geo-btn-success {
        background: var(--geo-success);
        color: white;
    }

    /* Color picker */
    .color-options {
        display: flex;
        gap: 0.5rem;
        margin-top: 1rem;
        flex-wrap: wrap;
    }

    .color-btn {
        width: 28px;
        height: 28px;
        border-radius: 50%;
        border: 2px solid transparent;
        cursor: pointer;
        transition: all 0.2s;
    }

    .color-btn:hover, .color-btn.active {
        transform: scale(1.1);
        border-color: var(--geo-dark);
    }

    /* Thickness */
    .thickness-options {
        display: flex;
        gap: 0.5rem;
        margin-top: 0.75rem;
    }

    .thickness-btn {
        flex: 1;
        padding: 0.5rem;
        border: 2px solid var(--geo-light);
        border-radius: 8px;
        background: var(--white);
        cursor: pointer;
        display: flex;
        align-items: center;
        justify-content: center;
    }

    .thickness-btn.active {
        border-color: var(--geo-primary);
        background: rgba(59, 130, 246, 0.1);
    }

    .thickness-line {
        width: 30px;
        background: var(--geo-dark);
        border-radius: 2px;
    }

    /* Grid Size Control */
    .grid-size-control {
        display: flex;
        align-items: center;
        gap: 0.75rem;
        margin-top: 0.5rem;
    }

    .grid-slider {
        flex: 1;
        height: 6px;
        -webkit-appearance: none;
        appearance: none;
        background: var(--geo-light);
        border-radius: 3px;
        outline: 2px solid transparent;
    }

    .grid-slider::-webkit-slider-thumb {
        -webkit-appearance: none;
        appearance: none;
        width: 18px;
        height: 18px;
        background: var(--geo-primary);
        border-radius: 50%;
        cursor: pointer;
    }

    .grid-slider::-moz-range-thumb {
        width: 18px;
        height: 18px;
        background: var(--geo-primary);
        border-radius: 50%;
        cursor: pointer;
        border: none;
    }

    .grid-size-label {
        font-size: 0.85rem;
        font-weight: 600;
        color: var(--geo-dark);
        min-width: 45px;
    }

    /* Angle Display */
    .angle-display {
        position: absolute;
        background: rgba(59, 130, 246, 0.9);
        color: white;
        padding: 4px 8px;
        border-radius: 4px;
        font-size: 0.85rem;
        font-weight: 600;
        pointer-events: none;
        z-index: 100;
    }

    /* Virtual Tools Overlay */
    .virtual-tool {
        position: absolute;
        pointer-events: none;
        opacity: 0.7;
        transition: opacity 0.2s;
    }

    .virtual-tool.active {
        opacity: 1;
        pointer-events: auto;
    }

    /* Responsive */
    @media (max-width: 768px) {
        .geo-tools, .geo-instructions {
            order: 2;
        }
        .geo-canvas-area {
            order: 1;
        }
        .canvas-wrapper {
            height: 350px;
        }
    }

    /* TBI / Touch-friendly styles */
    @media (pointer: coarse) {
        .tool-btn {
            padding: 1.1rem 1rem;
            min-height: 60px;
        }
        .color-btn {
            width: 40px;
            height: 40px;
        }
        .thickness-btn {
            min-height: 50px;
            padding: 0.75rem;
        }
        .canvas-toolbar-btn {
            padding: 0.75rem 1rem;
            min-height: 44px;
        }
        .canvas-wrapper {
            touch-action: none; /* Prevent browser gestures */
        }
    }

    /* Prevent text selection on touch */
    .geo-tools, .canvas-toolbar {
        -webkit-user-select: none;
        -moz-user-select: none;
        -ms-user-select: none;
        user-select: none;
    }

/* ===== DARK MODE ===== */
[data-theme="dark"] .geo-page { background: linear-gradient(135deg, #0f172a 0%, #1a1f35 100%) !important; }
[data-theme="dark"] .geo-tools,
[data-theme="dark"] .geo-instructions { background: #1e293b !important; border-color: #334155 !important; box-shadow: 0 4px 15px rgba(0,0,0,0.3) !important; }
[data-theme="dark"] .geo-tools h3,
[data-theme="dark"] .geo-instructions h3 { color: #e2e8f0 !important; border-bottom-color: #334155 !important; }
[data-theme="dark"] .geo-canvas-area { background: #162032 !important; }
[data-theme="dark"] .geo-tool-btn { background: #243044 !important; border-color: #334155 !important; color: #cbd5e1 !important; }
[data-theme="dark"] .geo-tool-btn:hover { background: #2d3d55 !important; border-color: #475569 !important; }
[data-theme="dark"] .geo-tool-btn.active { background: rgba(99,102,241,0.25) !important; border-color: #6366f1 !important; color: #a5b4fc !important; }
[data-theme="dark"] .geo-label,
[data-theme="dark"] .geo-instructions li { color: #94a3b8 !important; }
[data-theme="dark"] .geo-input { background: #243044 !important; border-color: #334155 !important; color: #e2e8f0 !important; }
[data-theme="dark"] .geo-header { color: #f1f5f9 !important; }
[data-theme="dark"] .geo-subtitle { color: #94a3b8 !important; }