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

:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #13131a;
    --bg-tertiary: #1a1a24;
    --border-color: rgba(255, 255, 255, 0.1);
    --text-primary: #ffffff;
    --text-secondary: #a0a0b0;
    --accent-primary: #4a9eff;
    --accent-secondary: #ff6b9d;
    --accent-glow: #4a9eff50;
}

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

.container {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

/* Header */
header {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    backdrop-filter: blur(10px);
}

h1 {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-info {
    display: flex;
    gap: 2rem;
}

.info-item {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.info-item strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* Main Content */
.main-content {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* Sidebar */
.sidebar {
    width: 320px;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    overflow-y: auto;
    padding: 1.5rem;
}

.sidebar::-webkit-scrollbar {
    width: 6px;
}

.sidebar::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
}

.sidebar::-webkit-scrollbar-thumb {
    background: var(--accent-primary);
    border-radius: 3px;
}

section {
    margin-bottom: 2rem;
}

section h3 {
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

/* Celestial Objects */
.objects-grid {
    display: grid;
    gap: 0.75rem;
}

.object-card {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem;
    cursor: grab;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.object-card:hover {
    border-color: var(--accent-primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(74, 158, 255, 0.2);
}

.object-card.dragging {
    opacity: 0.5;
    cursor: grabbing;
}

.object-preview {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    flex-shrink: 0;
}

.planet-small {
    width: 24px;
    height: 24px;
    background: radial-gradient(circle at 30% 30%, #8bb8ff, #4169e1);
    box-shadow: 0 0 20px rgba(65, 105, 225, 0.4);
}

.planet-medium {
    width: 32px;
    height: 32px;
    background: radial-gradient(circle at 30% 30%, #ffb347, #ff6347);
    box-shadow: 0 0 20px rgba(255, 99, 71, 0.4);
}

.planet-large {
    background: radial-gradient(circle at 30% 30%, #daa520, #b8860b);
    box-shadow: 0 0 20px rgba(218, 165, 32, 0.4);
}

.star {
    background: radial-gradient(circle at 30% 30%, #fffacd, #ffd700);
    box-shadow: 0 0 40px rgba(255, 215, 0, 0.8), 0 0 80px rgba(255, 215, 0, 0.4);
}

.black-hole {
    background: radial-gradient(circle at center, transparent 40%, #8b00ff 60%, #000 80%);
    box-shadow: 0 0 50px rgba(139, 0, 255, 0.8), inset 0 0 20px #000;
}

.object-info {
    flex: 1;
}

.object-name {
    display: block;
    font-weight: 500;
    margin-bottom: 0.25rem;
}

.object-mass {
    display: block;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* Controls */
.control-buttons {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.control-btn {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.75rem;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
    font-family: inherit;
}

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

.control-btn.primary {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    color: white;
}

.control-btn.primary:hover {
    background: #3a8eef;
}

.control-btn.active {
    border-color: var(--accent-secondary);
    color: var(--accent-secondary);
}

.control-btn .icon {
    font-size: 1.25rem;
}

.control-btn .label {
    font-size: 0.75rem;
    font-weight: 500;
}

/* Sliders */
.sliders {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.slider-group label {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
}

.slider-group input[type="range"] {
    width: 100%;
    height: 6px;
    background: var(--bg-tertiary);
    border-radius: 3px;
    outline: none;
    -webkit-appearance: none;
}

.slider-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    background: var(--accent-primary);
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s ease;
}

.slider-group input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 10px var(--accent-glow);
}

/* Presets */
.preset-buttons {
    display: grid;
    gap: 0.5rem;
}

.preset-btn {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.75rem;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: inherit;
    font-weight: 500;
}

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

/* Help */
.help ul {
    list-style: none;
}

.help li {
    font-size: 0.813rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    padding-left: 1rem;
    position: relative;
}

.help li:before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--accent-primary);
}

.help strong {
    color: var(--text-primary);
}

/* Canvas */
.canvas-container {
    flex: 1;
    position: relative;
    background: var(--bg-primary);
    background-image: 
        radial-gradient(circle at 20% 30%, rgba(74, 158, 255, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(255, 107, 157, 0.05) 0%, transparent 50%);
}

#canvas {
    width: 100%;
    height: 100%;
    cursor: crosshair;
}

.canvas-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
}

.velocity-indicator {
    position: absolute;
    background: var(--bg-tertiary);
    border: 1px solid var(--accent-primary);
    border-radius: 6px;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    transform: translate(-50%, -100%) translateY(-10px);
}

.velocity-indicator.hidden {
    display: none;
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        position: absolute;
        z-index: 10;
        transform: translateX(-100%);
        transition: transform 0.3s ease;
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
}