:root {
    --bg-color: #0f172a;
    --panel-bg: rgba(30, 41, 59, 0.7);
    --panel-border: rgba(255, 255, 255, 0.1);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --input-bg: rgba(15, 23, 42, 0.6);
    --font-family: 'Inter', sans-serif;
}

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

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

.app-container {
    display: flex;
    height: 100vh;
    width: 100vw;
    position: relative;
}

/* Canvas Area */
.canvas-container {
    flex: 1;
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #000;
    overflow: hidden;
}

.background-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    z-index: 1;
}

.checkerboard {
    /* Checkerboard pattern for default transparent look */
    background-image: linear-gradient(45deg, #333 25%, transparent 25%),
                      linear-gradient(-45deg, #333 25%, transparent 25%),
                      linear-gradient(45deg, transparent 75%, #333 75%),
                      linear-gradient(-45deg, transparent 75%, #333 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
}

#glcanvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: contain;
    z-index: 2;
}

/* Fullscreen mode styling */
#app-container:fullscreen .controls-panel {
    display: none;
}
#app-container:fullscreen #glcanvas,
#app-container:fullscreen .background-layer {
    object-fit: cover;
}

/* Loading Overlay */
.loading-overlay {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.8);
    z-index: 10;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    color: white;
    transition: opacity 0.5s;
}

.spinner {
    width: 40px; height: 40px;
    border: 4px solid rgba(255,255,255,0.1);
    border-left-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin { 100% { transform: rotate(360deg); } }

/* Controls Panel */
.controls-panel {
    width: 340px;
    height: 100%;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 24px;
    z-index: 5;
    overflow-y: auto;
    border-left: 1px solid var(--panel-border);
}

.glass-panel {
    background: var(--panel-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

.panel-header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    background: linear-gradient(to right, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-group label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.label-with-value {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.label-with-value span {
    font-size: 0.8rem;
    font-family: monospace;
    background: var(--input-bg);
    padding: 2px 6px;
    border-radius: 4px;
}

/* Sliders */
input[type=range] {
    -webkit-appearance: none;
    width: 100%;
    background: transparent;
}
input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none;
    height: 16px;
    width: 16px;
    border-radius: 50%;
    background: var(--accent-color);
    cursor: pointer;
    margin-top: -6px;
    box-shadow: 0 0 10px rgba(59, 130, 246, 0.5);
    transition: transform 0.1s;
}
input[type=range]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}
input[type=range]::-webkit-slider-runnable-track {
    width: 100%;
    height: 4px;
    cursor: pointer;
    background: var(--input-bg);
    border-radius: 2px;
}

/* Color Picker */
.color-picker-wrapper {
    display: flex;
    gap: 12px;
    align-items: center;
}

input[type="color"] {
    -webkit-appearance: none;
    border: none;
    width: 100%;
    height: 40px;
    border-radius: 8px;
    cursor: pointer;
    background: none;
}
input[type="color"]::-webkit-color-swatch-wrapper {
    padding: 0;
}
input[type="color"]::-webkit-color-swatch {
    border: 1px solid var(--panel-border);
    border-radius: 8px;
}

.icon-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 8px;
    border: 1px solid var(--panel-border);
    background: var(--input-bg);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s;
}
.icon-btn:hover {
    background: var(--accent-color);
    border-color: var(--accent-color);
}

/* Buttons */
.button-group {
    display: flex;
    gap: 8px;
}

.action-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 16px;
    border-radius: 8px;
    border: none;
    background: var(--accent-color);
    color: white;
    font-weight: 500;
    font-size: 0.875rem;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
    font-family: inherit;
}
.action-btn:hover {
    background: var(--accent-hover);
}
.action-btn:active {
    transform: scale(0.98);
}
.action-btn.secondary {
    background: rgba(255, 255, 255, 0.1);
}
.action-btn.secondary:hover {
    background: rgba(255, 255, 255, 0.15);
}

.mt-2 { margin-top: 8px; }

.divider {
    height: 1px;
    background: var(--panel-border);
    margin: 8px 0;
}

@media (max-width: 768px) {
    .app-container {
        flex-direction: column;
    }
    .controls-panel {
        width: 100%;
        height: 40%;
        border-left: none;
        border-top: 1px solid var(--panel-border);
    }
    .canvas-container {
        height: 60%;
    }
}