:root {
    --primary: #6366f1;
    --primary-glow: rgba(99, 102, 241, 0.4);
    --bg-dark: #09090b;
    --glass: rgba(255, 255, 255, 0.03);
    --glass-border: rgba(255, 255, 255, 0.1);
    --text-main: #f8fafc;
    --text-dim: #94a3b8;
    --accent: #8b5cf6;
}

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

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.background-blobs {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    filter: blur(80px);
}

.blob {
    position: absolute;
    border-radius: 50%;
    opacity: 0.4;
}

.blob-1 {
    width: 400px;
    height: 400px;
    background: var(--primary);
    top: -100px;
    left: -100px;
    animation: move 20s infinite alternate;
}

.blob-2 {
    width: 300px;
    height: 300px;
    background: var(--accent);
    bottom: -50px;
    right: -50px;
    animation: move 25s infinite alternate-reverse;
}

.blob-3 {
    width: 250px;
    height: 250px;
    background: #4f46e5;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation: pulse 15s infinite;
}

@keyframes move {
    from {
        transform: translate(0, 0);
    }

    to {
        transform: translate(100px, 100px);
    }
}

@keyframes pulse {

    0%,
    100% {
        transform: translate(-50%, -50%) scale(1);
    }

    50% {
        transform: translate(-50%, -50%) scale(1.2);
    }
}

.glass-container {
    background: var(--glass);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 32px;
    padding: 3rem;
    width: 90%;
    max-width: 500px;
    text-align: center;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    position: relative;
    overflow: hidden;
}

.headphones-note {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    background: linear-gradient(to right, var(--primary), var(--accent));
    padding: 0.5rem;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.05rem;
    text-transform: uppercase;
    color: white;
}

.logo {
    font-family: 'Playfair Display', serif;
    font-size: 2.5rem;
    background: linear-gradient(to right, #fff, var(--text-dim));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

.tagline {
    color: var(--text-dim);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.2rem;
    margin-bottom: 2rem;
}

.visualizer-container {
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 2.5rem;
    position: relative;
}

.visualizer {
    width: 150px;
    height: 150px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

.circle {
    position: absolute;
    border: 1px solid var(--glass-border);
    border-radius: 50%;
    transition: all 0.5s ease;
}

.outer {
    width: 100%;
    height: 100%;
}

.middle {
    width: 70%;
    height: 70%;
}

.inner {
    width: 40%;
    height: 40%;
    background: var(--glass-border);
}

.playing .circle {
    border-color: var(--primary);
    box-shadow: 0 0 20px var(--primary-glow);
}

.playing .outer {
    animation: ripple 2s infinite;
}

.playing .middle {
    animation: ripple 2s infinite 0.3s;
}

.playing .inner {
    background: var(--primary);
    animation: glow 2s infinite;
}

@keyframes ripple {
    0% {
        transform: scale(1);
        opacity: 0.8;
    }

    100% {
        transform: scale(1.5);
        opacity: 0;
    }
}

@keyframes glow {

    0%,
    100% {
        box-shadow: 0 0 10px var(--primary);
    }

    50% {
        box-shadow: 0 0 30px var(--primary);
    }
}

.play-hint {
    position: absolute;
    bottom: -30px;
    font-size: 0.8rem;
    color: var(--text-dim);
    transition: opacity 0.3s;
}

.playing .play-hint {
    opacity: 0;
}

.preset-selector {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.preset-btn {
    background: var(--glass);
    border: 1px solid var(--glass-border);
    color: var(--text-dim);
    padding: 0.75rem 0.5rem;
    border-radius: 12px;
    cursor: pointer;
    font-size: 0.8rem;
    transition: all 0.3s;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.preset-btn span {
    font-size: 0.6rem;
    text-transform: uppercase;
    opacity: 0.6;
    font-weight: 400;
}

.preset-btn:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--text-dim);
}

.preset-btn.active {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
    box-shadow: 0 4px 12px var(--primary-glow);
}

.freq-info {
    background: rgba(255, 255, 255, 0.02);
    border-radius: 16px;
    padding: 1.25rem;
    margin-bottom: 2rem;
    border: 1px solid var(--glass-border);
    text-align: left;
    min-height: 100px;
}

.freq-info h3 {
    font-size: 0.9rem;
    color: var(--primary);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05rem;
}

.freq-info p {
    font-size: 0.85rem;
    color: var(--text-dim);
    line-height: 1.4;
    margin-bottom: 1rem;
}

.math-breakdown {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    font-family: monospace;
    font-size: 0.8rem;
}

.math-item {
    color: var(--text-dim);
}

.math-item span {
    color: var(--text-main);
    font-weight: 600;
}

.math-item-result {
    color: var(--primary);
    font-weight: 800;
    background: rgba(99, 102, 241, 0.1);
    padding: 2px 8px;
    border-radius: 4px;
}

.volume-control {
    margin-bottom: 2.5rem;
    text-align: left;
}

.volume-control label {
    display: block;
    margin-bottom: 0.75rem;
    font-size: 0.8rem;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 0.1rem;
}

input[type="range"] {
    width: 100%;
    accent-color: var(--primary);
    cursor: pointer;
}

.btn-primary {
    width: 100%;
    padding: 1.25rem;
    border-radius: 16px;
    border: none;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    font-weight: 600;
    font-size: 1.1rem;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    box-shadow: 0 10px 20px -5px var(--primary-glow);
}

.btn-primary:active {
    transform: scale(0.98);
}

.btn-primary.playing {
    background: transparent;
    border: 1px solid var(--glass-border);
    color: var(--text-main);
}

footer {
    margin-top: 3rem;
    font-size: 0.7rem;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 0.1rem;
}