:root {
    --neon-blue: #00f3ff;
    --neon-pink: #ff00ff;
    --neon-green: #00ff9d;
    --neon-yellow: #ffe600;
    --neon-red: #ff3333;
    --bg-color: #050505;
}

body,
html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    background-color: var(--bg-color);
    overflow: hidden;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: white;
    user-select: none;
}

#game-container {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background: radial-gradient(circle at center, #1a1a1a 0%, #000000 100%);
}

canvas {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
}

/* UI Overlay */
#ui-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10;
    pointer-events: none;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 40px 60px;
    /* Increased padding */
    box-sizing: border-box;
}

.hud-top {
    display: flex;
    justify-content: space-between;
    width: 100%;
    font-size: 24px;
    text-shadow: 0 0 10px var(--neon-blue);
    align-items: center;
}

.score-box {
    text-align: left;
    font-weight: bold;
    font-size: 32px;
}

.energy-wrapper {
    display: flex;
    align-items: center;
    gap: 15px;
}

.energy-label {
    font-size: 18px;
    color: #aaa;
    letter-spacing: 2px;
}

.energy-bar-container {
    width: 300px;
    height: 20px;
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid var(--neon-blue);
    border-radius: 10px;
    overflow: hidden;
    position: relative;
    box-shadow: 0 0 10px rgba(0, 243, 255, 0.2);
}

.energy-fill {
    width: 0%;
    height: 100%;
    background: linear-gradient(90deg, var(--neon-blue), var(--neon-pink));
    box-shadow: 0 0 15px var(--neon-pink);
    transition: width 0.1s linear;
}

.energy-fill.fever {
    background: linear-gradient(90deg, var(--neon-yellow), var(--neon-red));
    box-shadow: 0 0 20px var(--neon-red);
}

.combo-display {
    position: absolute;
    top: 30%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    opacity: 0;
    transition: opacity 0.2s, transform 0.1s;
}

.combo-count {
    font-size: 80px;
    font-weight: bold;
    color: var(--neon-yellow);
    text-shadow: 0 0 20px var(--neon-yellow);
}

.combo-label {
    font-size: 24px;
    color: white;
    letter-spacing: 5px;
}

.fever-text {
    position: absolute;
    top: 20%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 60px;
    font-weight: 900;
    color: var(--neon-red);
    text-shadow: 0 0 30px var(--neon-red);
    opacity: 0;
    letter-spacing: 10px;
    font-style: italic;
}

.judgement-text {
    position: absolute;
    top: 45%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 40px;
    font-weight: bold;
    opacity: 0;
    text-shadow: 0 0 10px white;
    z-index: 12;
}

/* Start Screen */
#start-screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9);
    z-index: 20;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    backdrop-filter: blur(10px);
    pointer-events: auto;
}

h1 {
    font-size: 5vw;
    margin-bottom: 10px;
    background: linear-gradient(to right, var(--neon-blue), var(--neon-pink));
    -webkit-background-clip: text;
    color: transparent;
    text-shadow: 0 0 30px rgba(0, 243, 255, 0.5);
    animation: pulse 2s infinite;
    text-align: center;
}

.subtitle {
    color: #ccc;
    font-size: 1.5em;
    margin-bottom: 40px;
    letter-spacing: 3px;
}

.instructions-box {
    background: rgba(255, 255, 255, 0.05);
    padding: 30px;
    border-radius: 15px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    margin-bottom: 30px;
    text-align: center;
    max-width: 600px;
}

.instructions-title {
    color: var(--neon-green);
    font-size: 24px;
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.key-diagram {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin: 20px 0;
}

.key-box {
    width: 60px;
    height: 60px;
    border: 2px solid white;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 30px;
    font-weight: bold;
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.2);
}

.key-d {
    border-color: var(--neon-blue);
    color: var(--neon-blue);
    box-shadow: 0 0 15px var(--neon-blue);
}

.key-f {
    border-color: var(--neon-pink);
    color: var(--neon-pink);
    box-shadow: 0 0 15px var(--neon-pink);
}

.key-j {
    border-color: var(--neon-green);
    color: var(--neon-green);
    box-shadow: 0 0 15px var(--neon-green);
}

.key-k {
    border-color: var(--neon-yellow);
    color: var(--neon-yellow);
    box-shadow: 0 0 15px var(--neon-yellow);
}

.instruction-text {
    font-size: 18px;
    line-height: 1.6;
    color: #ddd;
}

.btn {
    padding: 15px 50px;
    font-size: 28px;
    background: transparent;
    border: 2px solid var(--neon-green);
    color: var(--neon-green);
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 2px;
    transition: all 0.3s;
    box-shadow: 0 0 10px var(--neon-green);
    border-radius: 50px;
}

.btn:hover {
    background: var(--neon-green);
    color: black;
    box-shadow: 0 0 40px var(--neon-green);
    transform: scale(1.1);
}

@keyframes pulse {
    0% {
        transform: scale(1);
        filter: brightness(1);
    }

    50% {
        transform: scale(1.05);
        filter: brightness(1.2);
    }

    100% {
        transform: scale(1);
        filter: brightness(1);
    }
}

@keyframes feverPulse {
    0% {
        transform: translate(-50%, -50%) scale(1);
        opacity: 0.8;
    }

    50% {
        transform: translate(-50%, -50%) scale(1.1);
        opacity: 1;
    }

    100% {
        transform: translate(-50%, -50%) scale(1);
        opacity: 0.8;
    }
}