:root {
    --bg-body: #0a0a0a;
    --bg-sidebar: #161616;
    --bg-card: #1a1a1a;
    --bg-card-hover: #222;
    --border-color: #27272a;
    --primary: #ffffff;
    --secondary: #a1a1aa;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-glow: rgba(59, 130, 246, 0.5);
    --font-family: 'Inter', sans-serif;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-body);
    color: var(--primary);
    height: 100vh;
    overflow: hidden;
}

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

/* SIDEBAR */
.sidebar {
    width: 300px;
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    padding: 24px;
    overflow-y: auto;
    flex-shrink: 0;
}

.sidebar-header {
    margin-bottom: 32px;
}

.sidebar-header h2 {
    font-size: 1.5rem;
    line-height: 1.2;
    margin-bottom: 12px;
    background: linear-gradient(to bottom, #ffffff, #a0a0a0);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.back-link {
    color: var(--secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s;
}

.back-link:hover {
    color: var(--primary);
}

.template-group {
    margin-bottom: 32px;
}

.template-group h3 {
    font-size: 0.8rem;
    text-transform: uppercase;
    color: var(--secondary);
    letter-spacing: 1px;
    margin-bottom: 12px;
}

.template-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.template-item {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    overflow: hidden;
    transition: all 0.2s;
    aspect-ratio: 1;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

.template-item:hover,
.template-item.active {
    border-color: var(--accent);
    background-color: var(--bg-card-hover);
}

.template-preview {
    width: 80%;
    height: 80%;
    pointer-events: none;
    opacity: 0.8;
}

.template-label {
    position: absolute;
    bottom: 0;
    width: 100%;
    background: rgba(0, 0, 0, 0.8);
    font-size: 0.7rem;
    text-align: center;
    padding: 4px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* MAIN CONTENT */
.main-content {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.toolbar {
    height: 64px;
    border-bottom: 1px solid var(--border-color);
    padding: 0 24px;
    display: flex;
    align-items: center;
    gap: 24px;
    background-color: var(--bg-body);
}

.tool-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.tool-group label {
    font-size: 0.9rem;
    color: var(--secondary);
}

select {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    color: var(--primary);
    padding: 6px 12px;
    border-radius: 6px;
    font-family: inherit;
    cursor: pointer;
}

.check-group {
    cursor: pointer;
}

.spacer {
    flex-grow: 1;
}

.btn {
    padding: 8px 16px;
    border-radius: 6px;
    border: none;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
    font-family: inherit;
}

.btn.primary {
    background-color: var(--accent);
    color: white;
    box-shadow: 0 4px 12px var(--accent-glow);
}

.btn.primary:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px var(--accent-glow);
}

.btn.secondary {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    color: var(--primary);
}

.btn.secondary:hover {
    background-color: var(--bg-card-hover);
    border-color: var(--accent);
}

.btn-group {
    display: flex;
    gap: 8px;
}

/* CANVAS */
.canvas-wrapper {
    flex-grow: 1;
    background-image:
        linear-gradient(45deg, #111 25%, transparent 25%),
        linear-gradient(-45deg, #111 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #111 75%),
        linear-gradient(-45deg, transparent 75%, #111 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
    background-color: #0d0d0d;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: auto;
    padding: 40px;
    position: relative;
}

.btn.small {
    padding: 4px 12px;
    font-size: 0.8rem;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    color: var(--primary);
}

.btn.small:hover {
    background-color: var(--bg-card-hover);
    border-color: var(--accent);
}

.btn.danger:hover {
    background-color: #ff4444;
    border-color: #ff4444;
    color: white;
}

canvas {
    max-height: 90%;
    max-width: 90%;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
    background-color: #000;
}

canvas.resize-h {
    cursor: ns-resize;
}

canvas.resize-v {
    cursor: ew-resize;
}

canvas.cell-hover {
    cursor: crosshair;
}

.uv-tooltip {
    position: fixed;
    background: rgba(0, 0, 0, 0.9);
    border: 1px solid var(--border-color);
    padding: 8px 12px;
    border-radius: 6px;
    font-family: monospace;
    font-size: 0.9rem;
    pointer-events: none;
    z-index: 100;
    line-height: 1.4;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
}

.uv-tooltip.hidden {
    opacity: 0;
}

.uv-tooltip span {
    color: var(--accent);
    font-weight: bold;
}

/* MOBILE MENU TOGGLE */
.mobile-menu-toggle {
    display: none;
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 1000;
    background: var(--accent);
    border: none;
    border-radius: 8px;
    padding: 10px 16px;
    color: white;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 4px 12px var(--accent-glow);
}

.mobile-menu-toggle:hover {
    background: var(--accent-hover);
}

.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    z-index: 999;
}

.sidebar-overlay.active {
    display: block;
}

/* RESPONSIVE DESIGN */
@media (max-width: 1024px) {
    .sidebar {
        width: 260px;
    }

    .toolbar {
        flex-wrap: wrap;
        height: auto;
        padding: 16px;
        gap: 12px;
    }

    .canvas-wrapper {
        padding: 24px;
    }
}

@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: block;
    }

    .sidebar {
        position: fixed;
        top: 0;
        left: -300px;
        bottom: 0;
        z-index: 1000;
        transition: left 0.3s ease;
        box-shadow: 2px 0 16px rgba(0, 0, 0, 0.5);
    }

    .sidebar.active {
        left: 0;
    }

    .toolbar {
        padding: 12px 16px;
        gap: 10px;
    }

    .tool-group {
        flex-wrap: wrap;
        gap: 6px;
    }

    .tool-group label {
        font-size: 0.85rem;
        min-width: 100%;
    }

    select {
        font-size: 0.85rem;
        padding: 5px 10px;
    }

    .btn {
        padding: 7px 14px;
        font-size: 0.85rem;
    }

    .btn.small {
        padding: 4px 10px;
        font-size: 0.75rem;
    }

    .canvas-wrapper {
        padding: 16px;
    }

    .template-list {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 480px) {
    .mobile-menu-toggle {
        top: 12px;
        left: 12px;
        padding: 8px 14px;
        font-size: 0.9rem;
    }

    .sidebar {
        width: 280px;
        padding: 20px;
    }

    .sidebar-header h2 {
        font-size: 1.3rem;
    }

    .toolbar {
        padding: 10px 12px;
        gap: 8px;
    }

    .tool-group {
        width: 100%;
    }

    select {
        width: 100%;
    }

    .btn-group {
        width: 100%;
        flex-direction: column;
    }

    .btn-group .btn {
        width: 100%;
    }

    .canvas-wrapper {
        padding: 12px;
    }

    canvas {
        max-width: 100%;
        max-height: 85%;
    }

    .template-list {
        grid-template-columns: repeat(2, 1fr);
    }

    .uv-tooltip {
        font-size: 0.8rem;
        padding: 6px 10px;
    }
}