:root {
    --bg-color: #050a0f;
    --panel-bg: rgba(10, 20, 30, 0.85);
    --accent-color: #00d4ff;
    --text-color: #e0f0ff;
    --font-main: 'Inter', sans-serif;
    --font-mono: 'JetBrains+Mono', monospace;
}

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

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

#canvas-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

#ui-overlay {
    position: absolute;
    top: 20px;
    left: 20px;
    z-index: 10;
    width: 350px;
    padding: 24px;
    background: var(--panel-bg);
    border-backdrop-filter: blur(10px);
    border: 1px solid rgba(0, 212, 255, 0.2);
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
    pointer-events: auto;
}

h1 {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 4px;
    letter-spacing: -0.5px;
    color: var(--accent-color);
    text-transform: uppercase;
}

p {
    font-size: 0.85rem;
    opacity: 0.7;
    margin-bottom: 24px;
}

.control-group {
    margin-bottom: 20px;
}

label {
    display: block;
    font-size: 0.9rem;
    margin-bottom: 8px;
    font-weight: 500;
}

.interaction-hint {
    font-size: 0.7rem;
    opacity: 0.5;
    margin-bottom: 12px;
    font-style: italic;
}

input[type="range"] {
    width: 100%;
    background: rgba(255, 255, 255, 0.1);
    height: 4px;
    border-radius: 2px;
    -webkit-appearance: none;
    outline: none;
    margin: 15px 0;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    background: var(--accent-color);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 0 15px var(--accent-color);
    transition: transform 0.2s;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.readout {
    font-family: var(--font-mono);
    font-size: 2rem;
    text-align: center;
    color: var(--text-color);
    margin-top: 10px;
    padding: 10px;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 8px;
}

#sea-level-value {
    color: var(--accent-color);
    font-weight: 700;
}

footer {
    margin-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 16px;
}

.stat-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.stat-item .label {
    font-size: 0.75rem;
    opacity: 0.5;
    text-transform: uppercase;
}

.stat-item .value {
    font-size: 0.8rem;
    font-family: var(--font-mono);
}

#loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-color);
    z-index: 100;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    transition: opacity 0.5s ease-out;
}

.loader {
    width: 50px;
    height: 50px;
    border: 3px solid rgba(0, 212, 255, 0.1);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
}

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

.hidden {
    opacity: 0;
    pointer-events: none;
}