/* ===== CSS Reset & Base ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette */
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --accent-cyan: #00f5ff;
    --accent-purple: #b24bf3;
    --accent-gold: #ffd700;
    --bg-dark: #0a0e27;
    --bg-darker: #050814;
    --glass-bg: rgba(10, 14, 39, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --text-primary: #ffffff;
    --text-secondary: #b8c5d6;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    
    /* Shadows */
    --shadow-glow: 0 0 20px rgba(0, 245, 255, 0.3);
    --shadow-strong: 0 8px 32px rgba(0, 0, 0, 0.5);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-darker);
    color: var(--text-primary);
    overflow: hidden;
    line-height: 1.6;
}

h1, h2, h3 {
    font-family: 'Orbitron', monospace;
    font-weight: 700;
}

/* ===== Canvas ===== */
#canvas {
    display: block;
    width: 100%;
    height: 100vh;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1;
}

/* ===== Loading Screen ===== */
#loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: linear-gradient(135deg, #0a0e27 0%, #1a1f3a 50%, #0a0e27 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

#loading-screen.hidden {
    opacity: 0;
    visibility: hidden;
}

.loading-content {
    text-align: center;
    max-width: 500px;
    padding: var(--spacing-lg);
}

.loading-title {
    font-size: 3rem;
    font-weight: 900;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-lg);
    letter-spacing: 4px;
    animation: pulse 2s ease-in-out infinite;
}

.loading-spinner {
    width: 80px;
    height: 80px;
    margin: var(--spacing-lg) auto;
    border: 4px solid rgba(255, 255, 255, 0.1);
    border-top: 4px solid var(--accent-cyan);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.loading-text {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

.loading-bar {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: var(--spacing-sm);
}

.loading-progress {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-cyan), var(--accent-purple));
    border-radius: 10px;
    width: 0%;
    transition: width 0.3s ease;
    box-shadow: 0 0 20px var(--accent-cyan);
}

.loading-percentage {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--accent-cyan);
}

/* ===== UI Overlay ===== */
#ui-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    pointer-events: none;
    z-index: 10;
}

#ui-overlay > * {
    pointer-events: auto;
}

/* ===== Header ===== */
.header {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    padding: var(--spacing-md) var(--spacing-lg);
    background: linear-gradient(180deg, var(--glass-bg) 0%, transparent 100%);
    backdrop-filter: blur(10px);
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--glass-border);
}

.app-title {
    font-size: 1.5rem;
    font-weight: 900;
    letter-spacing: 3px;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.menu-toggle {
    display: none;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    font-size: 1.5rem;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.3s ease;
}

.menu-toggle:hover {
    background: rgba(255, 255, 255, 0.1);
    box-shadow: var(--shadow-glow);
}

/* ===== Control Panel ===== */
.control-panel {
    position: absolute;
    top: 100px;
    left: var(--spacing-lg);
    width: 320px;
    max-height: calc(100vh - 140px);
    overflow-y: auto;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-strong);
    transition: transform 0.3s ease;
}

.control-panel.hidden {
    transform: translateX(-400px);
}

.panel-section {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--glass-border);
}

.panel-section:last-child {
    border-bottom: none;
    margin-bottom: 0;
}

.panel-section h3 {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-sm);
    color: var(--accent-cyan);
    text-transform: uppercase;
    letter-spacing: 2px;
}

.control-group {
    margin-bottom: var(--spacing-sm);
}

.control-group label {
    display: block;
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
}

#speed-slider {
    width: 70%;
    margin-right: var(--spacing-sm);
}

#speed-value {
    font-weight: 600;
    color: var(--accent-cyan);
}

.toggle-btn {
    display: block;
    width: 100%;
    padding: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.toggle-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--accent-cyan);
}

.toggle-btn.active {
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    color: var(--text-primary);
    border-color: transparent;
    box-shadow: var(--shadow-glow);
}

/* ===== Planet List ===== */
.planet-list {
    display: grid;
    gap: var(--spacing-xs);
}

.planet-btn {
    padding: var(--spacing-sm);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: left;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.planet-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--accent-cyan);
    transform: translateX(5px);
}

.planet-btn.selected {
    background: linear-gradient(135deg, rgba(0, 245, 255, 0.2), rgba(178, 75, 243, 0.2));
    border-color: var(--accent-cyan);
}

.planet-icon {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    flex-shrink: 0;
}

/* ===== Instructions ===== */
.instructions {
    list-style: none;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.instructions li {
    margin-bottom: var(--spacing-xs);
    padding-left: var(--spacing-sm);
    position: relative;
}

.instructions li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--accent-cyan);
}

/* ===== Planet Info Panel ===== */
.planet-info {
    position: absolute;
    top: 100px;
    right: var(--spacing-lg);
    width: 380px;
    max-height: calc(100vh - 140px);
    overflow-y: auto;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-strong);
    transition: transform 0.3s ease, opacity 0.3s ease;
}

.planet-info.hidden {
    transform: translateX(450px);
    opacity: 0;
}

.close-btn {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    font-size: 1.5rem;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 1;
}

.close-btn:hover {
    background: rgba(255, 0, 0, 0.3);
    border-color: #ff0000;
}

#planet-name {
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.planet-stats {
    margin-bottom: var(--spacing-md);
}

.stat {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--glass-border);
}

.stat:last-child {
    border-bottom: none;
}

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

.stat-value {
    color: var(--text-primary);
    font-weight: 600;
}

.planet-description {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--text-secondary);
}

/* ===== Animations ===== */
@keyframes spin {
    to { transform: rotate(360deg); }
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

/* ===== Scrollbar Styling ===== */
.control-panel::-webkit-scrollbar,
.planet-info::-webkit-scrollbar {
    width: 8px;
}

.control-panel::-webkit-scrollbar-track,
.planet-info::-webkit-scrollbar-track {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 10px;
}

.control-panel::-webkit-scrollbar-thumb,
.planet-info::-webkit-scrollbar-thumb {
    background: var(--accent-cyan);
    border-radius: 10px;
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
    .control-panel {
        width: 280px;
    }
    
    .planet-info {
        width: 320px;
    }
}

@media (max-width: 768px) {
    .menu-toggle {
        display: block;
    }
    
    .control-panel {
        left: 0;
        top: 80px;
        width: 100%;
        max-width: 320px;
        border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
    }
    
    .planet-info {
        right: 0;
        width: 100%;
        max-width: 320px;
        border-radius: var(--radius-lg) 0 0 var(--radius-lg);
    }
    
    .app-title {
        font-size: 1.2rem;
    }
}

@media (max-width: 480px) {
    .loading-title {
        font-size: 2rem;
    }
    
    .control-panel,
    .planet-info {
        max-width: 100%;
        border-radius: 0;
    }
}