#multiverse-bg {
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    overflow: hidden;
}

#multiverse-canvas {
    width: 100%;
    height: 100%;
    display: block;
}

.multiverse-overlay {
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse at 50% 40%, transparent 0%, rgba(3, 5, 14, 0.35) 60%, rgba(3, 5, 14, 0.85) 100%);
    pointer-events: none;
}

.multiverse-vignette {
    position: absolute;
    inset: 0;
    box-shadow: inset 0 0 240px 60px rgba(3, 5, 14, 0.95);
    pointer-events: none;
}

/* Loading overlay */
.loading-overlay {
    position: fixed;
    inset: 0;
    z-index: 9999;
    background: var(--cosmic-black);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2rem;
    transition: opacity 900ms var(--ease-out-expo), visibility 900ms;
}

.loading-overlay.hidden {
    opacity: 0;
    visibility: hidden;
}

.loader-core {
    position: relative;
    width: 140px;
    height: 140px;
}

.loader-ring {
    position: absolute;
    inset: 0;
    border-radius: 50%;
    border: 2px solid transparent;
    border-top-color: var(--electric-cyan);
    border-right-color: var(--ultraviolet);
    animation: spin 1.6s linear infinite;
}

.loader-ring-2 {
    inset: 14px;
    border-top-color: var(--nebula-purple);
    border-right-color: transparent;
    animation-direction: reverse;
    animation-duration: 2.2s;
}

.loader-ring-3 {
    inset: 28px;
    border-top-color: var(--ice-blue);
    animation-duration: 1.2s;
}

.loader-center {
    position: absolute;
    inset: 46px;
    border-radius: 50%;
    background: radial-gradient(circle, var(--electric-cyan), transparent 70%);
    box-shadow: 0 0 40px var(--glow-cyan);
    animation: pulse 1.6s ease-in-out infinite;
}

.loader-text {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.8rem;
    letter-spacing: 0.3em;
}

.loader-progress {
    width: 220px;
    height: 2px;
    background: rgba(127, 231, 255, 0.15);
    margin-top: 1rem;
    border-radius: 2px;
    overflow: hidden;
}

.loader-progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--electric-cyan), var(--ultraviolet));
    transition: width 200ms;
}

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

@keyframes pulse {

    0%,
    100% {
        opacity: .5;
        transform: scale(.9);
    }

    50% {
        opacity: 1;
        transform: scale(1.08);
    }
}

@keyframes orbPulse {

    0%,
    100% {
        box-shadow: 0 0 20px var(--glow-cyan);
    }

    50% {
        box-shadow: 0 0 36px var(--glow-purple);
    }
}

/* WebGL fallback */
.webgl-fallback {
    position: fixed;
    inset: 0;
    z-index: 0;
    background: var(--cosmic-black);
}

.fallback-stars {
    position: absolute;
    inset: 0;
    background-image: radial-gradient(2px 2px at 20% 30%, white, transparent),
        radial-gradient(1px 1px at 60% 70%, white, transparent),
        radial-gradient(1.5px 1.5px at 80% 20%, var(--ice-blue), transparent),
        radial-gradient(1px 1px at 40% 80%, white, transparent),
        radial-gradient(2px 2px at 90% 60%, var(--electric-cyan), transparent);
    background-size: 550px 550px, 350px 350px, 250px 250px, 450px 450px, 650px 650px;
    animation: starDrift 120s linear infinite;
}

.fallback-nebula {
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 30% 40%, rgba(168, 85, 247, 0.15), transparent 55%),
        radial-gradient(circle at 70% 60%, rgba(0, 229, 255, 0.12), transparent 55%);
    animation: nebulaBreath 14s ease-in-out infinite alternate;
}

@keyframes starDrift {
    to {
        background-position: 550px 550px, -350px 350px, 250px -250px, -450px 450px, 650px -650px;
    }
}

@keyframes nebulaBreath {
    from {
        opacity: .5;
    }

    to {
        opacity: 1;
    }
}

/* Scene controls */
.scene-controls {
    position: fixed;
    right: 1.25rem;
    bottom: 1.5rem;
    z-index: 900;
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.scene-btn {
    width: 46px;
    height: 46px;
    border-radius: 50%;
    border: 1px solid var(--glass-border);
    background: var(--glass-bg);
    backdrop-filter: blur(14px);
    color: var(--text-secondary);
    cursor: pointer;
    display: grid;
    place-items: center;
    font-size: 1.05rem;
    transition: all var(--t-fast);
}

.scene-btn:hover {
    color: var(--electric-cyan);
    border-color: var(--electric-cyan);
    box-shadow: 0 0 18px var(--glow-cyan);
}

.quality-panel {
    position: fixed;
    right: 5rem;
    bottom: 1.5rem;
    z-index: 901;
    background: var(--glass-bg-heavy);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    min-width: 180px;
}

.quality-panel h4 {
    font-size: 0.85rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.15em;
    margin-bottom: 0.4rem;
}

.quality-opt {
    padding: 0.5rem 0.75rem;
    border-radius: 8px;
    border: 1px solid var(--glass-border);
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    text-align: left;
}

.quality-opt:hover,
.quality-opt.active {
    background: var(--glass-bg);
    color: var(--electric-cyan);
    border-color: var(--electric-cyan);
}

/* Audio + back to top */
.audio-toggle {
    position: fixed;
    left: 1.25rem;
    bottom: 1.5rem;
    z-index: 900;
    width: 46px;
    height: 46px;
    border-radius: 50%;
    border: 1px solid var(--glass-border);
    background: var(--glass-bg);
    backdrop-filter: blur(14px);
    color: var(--text-secondary);
    cursor: pointer;
    display: grid;
    place-items: center;
}

.audio-toggle:hover {
    color: var(--electric-cyan);
    border-color: var(--electric-cyan);
}

.back-to-top {
    position: fixed;
    left: 1.25rem;
    bottom: 5rem;
    z-index: 900;
    width: 46px;
    height: 46px;
    border-radius: 50%;
    border: 1px solid var(--glass-border);
    background: var(--glass-bg);
    color: var(--text-secondary);
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all var(--t-med);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    color: var(--electric-cyan);
    border-color: var(--electric-cyan);
}

/* Messages */
.messages-container {
    position: fixed;
    top: 5rem;
    right: 1.25rem;
    z-index: 1500;
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
    max-width: 380px;
}

.toast-message {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.25rem;
    border-radius: var(--radius-sm);
    background: var(--glass-bg-heavy);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    animation: toastIn 500ms var(--ease-out-expo);
}

.toast-message i {
    color: var(--electric-cyan);
    font-size: 1.2rem;
}

.toast-close {
    margin-left: auto;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
}

@keyframes toastIn {
    from {
        opacity: 0;
        transform: translateX(40px);
    }
}