:root {
    --bg-gradient-1: #050510;
    --bg-gradient-2: #110520;
    --primary-color: #0ff;
    --primary-hover: #fff;
    --text-color: #fff;
    --text-muted: #88aaff;
    --border-color: #f0f;
    --health-color: #f00;
    --xp-color: #f0f;
    --enemy-color: #f0f;
    --player-color: #0ff;
    --bullet-color: #ff0;
    --panel-bg: rgba(5, 5, 15, 0.9);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-user-select: none;
    user-select: none;
}

body {
    font-family: 'Orbitron', sans-serif;
    background-color: var(--bg-gradient-1);
    color: var(--text-color);
    overflow: hidden;
    /* Prevent scrolling */
    width: 100vw;
    height: 100vh;
}

#gameCanvas {
    display: block;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at center, var(--bg-gradient-2) 0%, var(--bg-gradient-1) 100%);
}

.ui-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    display: flex;
    flex-direction: column;
    z-index: 5;
}

/* UI states */
.hidden {
    display: none !important;
}

/* Center overlays like Menus */
.glassmorphism-dark {
    pointer-events: auto;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: var(--panel-bg);
    border: 2px solid var(--border-color);
    box-shadow: 0 0 20px var(--border-color), inset 0 0 10px var(--border-color);
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    z-index: 10;
}

.glassmorphism-dark h1,
.glassmorphism-dark h2 {
    font-size: 3rem;
    font-weight: 900;
    margin-bottom: 1rem;
    color: var(--primary-color);
    text-shadow: 0 0 10px var(--primary-color), 0 0 20px var(--primary-color);
    letter-spacing: 2px;
}

.glassmorphism-dark p {
    font-size: 1.2rem;
    color: var(--text-muted);
    margin-bottom: 2rem;
    text-shadow: 0 0 5px var(--text-muted);
}

/* HUD Overlay Elements */
#hud {
    padding: 1.5rem;
    justify-content: space-between;
}

.top-bar {
    display: flex;
    justify-content: space-between;
    font-size: 1.5rem;
    font-weight: 900;
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.5);
    letter-spacing: 1px;
}

.score-container {
    color: var(--player-color);
    text-shadow: 0 0 10px var(--player-color);
}

.level-container {
    color: var(--bullet-color);
    text-shadow: 0 0 10px var(--bullet-color);
}

.xp-bar-container,
.health-container {
    width: 100%;
    max-width: 400px;
    height: 24px;
    background: #000;
    border: 2px solid var(--border-color);
    box-shadow: 0 0 10px var(--border-color);
    position: relative;
    margin: 10px auto;
    overflow: hidden;
    /* Sharp edges */
    border-radius: 0;
}

.xp-bar-container {
    margin-bottom: 1rem;
}

.xp-bar-fill {
    height: 100%;
    width: 0%;
    background: var(--xp-color);
    box-shadow: 0 0 10px var(--xp-color);
    transition: width 0.3s ease;
}

.health-container {
    border-color: var(--health-color);
    box-shadow: 0 0 10px var(--health-color);
}

.health-bar-fill {
    height: 100%;
    width: 100%;
    background: var(--health-color);
    box-shadow: 0 0 10px var(--health-color);
    transition: width 0.3s ease;
}

.xp-text,
.health-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 0.8rem;
    font-weight: 700;
    text-shadow: 1px 1px 0px black, -1px -1px 0px black, 1px -1px 0px black, -1px 1px 0px black;
    color: #fff;
    letter-spacing: 1px;
}

/* Upgrades Options */
.upgrade-options {
    display: flex;
    gap: 1.5rem;
    flex-wrap: wrap;
    justify-content: center;
    max-width: 800px;
}

.upgrade-card {
    background: #000;
    border: 2px solid var(--primary-color);
    padding: 1.5rem;
    width: 220px;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: center;
    box-shadow: 0 0 10px var(--primary-color);
}

.upgrade-card:hover {
    transform: scale(1.05);
    background: #112;
    border-color: #fff;
    box-shadow: 0 0 25px var(--primary-color), 0 0 10px #fff;
}

.upgrade-title {
    font-size: 1.2rem;
    font-weight: 900;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    text-shadow: 0 0 5px var(--primary-color);
}

.upgrade-desc {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Button Styling */
.primary-button {
    position: relative;
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    padding: 1rem 2.5rem;
    font-size: 1.2rem;
    font-weight: 900;
    font-family: inherit;
    cursor: pointer;
    overflow: hidden;
    transition: all 0.2s ease;
    box-shadow: 0 0 10px var(--primary-color), inset 0 0 10px var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 2px;
}

.primary-button:hover {
    background: var(--primary-color);
    color: #000;
    box-shadow: 0 0 30px var(--primary-color);
}

.primary-button:active {
    transform: scale(0.95);
}

.button-text {
    position: relative;
    z-index: 2;
}

.button-glow {
    display: none;
    /* Removed for this aesthetic */
}

/* CRT Scanline Overlay */
#crt-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    pointer-events: none;
    z-index: 100;
    background: linear-gradient(rgba(18, 16, 16, 0) 50%,
            rgba(0, 0, 0, 0.25) 50%);
    background-size: 100% 4px;
    animation: flicker 0.15s infinite;
}

/* Subtle screen edge darkening */
#crt-overlay::before {
    content: " ";
    display: block;
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: radial-gradient(circle, rgba(0, 0, 0, 0) 60%, rgba(0, 0, 0, 0.4) 100%);
}

@keyframes flicker {
    0% {
        opacity: 0.95;
    }

    50% {
        opacity: 1;
    }

    100% {
        opacity: 0.95;
    }
}