/* main.css — Fullscreen canvas with minimal, elegant UI overlays.
 */

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

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: #000;
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

canvas {
    display: block;
    width: 100%;
    height: 100%;
}

/* Loading overlay — centered, dark, fades out via JS. */
#loading-overlay {
    position: fixed;
    inset: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    color: #e2e8f0;
    text-align: center;
    transition: opacity 0.8s ease, visibility 0.8s ease;
}

#loading-overlay.hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.loading-content h1 {
    font-size: 2.5rem;
    font-weight: 300;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}

.loading-content p {
    font-size: 1rem;
    color: #94a3b8;
}

/* Instruction hint — bottom-left, fades out after first interaction. */
#instructions {
    position: fixed;
    bottom: 1.5rem;
    left: 1.5rem;
    z-index: 50;
    background: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    padding: 0.75rem 1.25rem;
    border-radius: 0.75rem;
    color: #e2e8f0;
    font-size: 0.875rem;
    line-height: 1.4;
    pointer-events: none;
    opacity: 1;
    transition: opacity 1s ease;
}

#instructions.hidden {
    opacity: 0;
}

#instructions p {
    margin: 0;
}

/* WebGL error screen. */
#no-webgl {
    position: fixed;
    inset: 0;
    z-index: 200;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: #0f172a;
    color: #e2e8f0;
    text-align: center;
    padding: 2rem;
}

#no-webgl h1 {
    font-size: 2rem;
    margin-bottom: 1rem;
}

#no-webgl p {
    font-size: 1rem;
    color: #94a3b8;
    max-width: 28rem;
}