:root {
    --bg-color: #050510;
    --neon-blue: #00f3ff;
    --neon-pink: #ff00ff;
    --neon-purple: #9d00ff;
    --text-main: #ffffff;
    --text-dim: #a0aab5;
    --danger: #ff3366;
    --success: #00ff66;
    --glass-bg: rgba(10, 15, 30, 0.7);
    --glass-border: rgba(0, 243, 255, 0.3);
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: 'Rajdhani', sans-serif;
    overflow: hidden; /* Prevent scrolling */
    width: 100vw;
    height: 100vh;
    touch-action: none; /* Prevent default touch actions like zooming/scrolling */
}

h1, h2, h3, h4 {
    font-family: 'Orbitron', sans-serif;
}

/* Canvas Base */
#gameCanvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

/* UI Layer Base */
#ui-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10;
    pointer-events: none; /* Let clicks pass through to canvas when needed */
}

/* Screens */
.screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    pointer-events: auto;
    transition: opacity 0.5s ease;
}

.screen.hidden {
    opacity: 0;
    pointer-events: none;
    visibility: hidden;
}

.screen.active {
    opacity: 1;
    pointer-events: auto;
    visibility: visible;
}

/* Main Menu */
#main-menu {
    justify-content: center;
    align-items: center;
    background: radial-gradient(circle at center, rgba(5,5,16,0.4) 0%, rgba(0,0,0,0.9) 100%);
    backdrop-filter: blur(5px);
}

.logo-container {
    text-align: center;
    margin-bottom: 50px;
    animation: float 4s ease-in-out infinite;
}

.game-title {
    font-size: 4rem;
    font-weight: 900;
    color: transparent;
    -webkit-text-stroke: 2px var(--neon-blue);
    text-shadow: 0 0 20px var(--neon-blue), 0 0 40px rgba(0, 243, 255, 0.5);
    letter-spacing: 5px;
    position: relative;
}

.game-title::before {
    content: attr(data-text);
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    color: var(--neon-pink);
    -webkit-text-stroke: 0px;
    clip-path: polygon(0 0, 100% 0, 100% 45%, 0 45%);
    animation: glitch 3s infinite;
}

.game-subtitle {
    font-size: 2.5rem;
    color: var(--neon-purple);
    text-shadow: 0 0 15px var(--neon-purple);
    letter-spacing: 15px;
    margin-top: -10px;
}

/* Buttons */
.cyber-button {
    background: linear-gradient(45deg, transparent 5%, var(--neon-purple) 5%);
    color: var(--text-main);
    border: 0;
    padding: 15px 40px;
    font-size: 1.5rem;
    font-family: 'Orbitron', sans-serif;
    font-weight: 700;
    letter-spacing: 3px;
    text-transform: uppercase;
    position: relative;
    cursor: pointer;
    box-shadow: 6px 0px 0px var(--neon-blue);
    transition: all 0.3s ease;
    outline: none;
}

.cyber-button.small {
    padding: 10px 20px;
    font-size: 1.2rem;
    box-shadow: 4px 0px 0px var(--neon-blue);
}

.cyber-button::after {
    content: 'PLANET_DEF';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: transparent;
    border: 1px solid var(--neon-blue);
    opacity: 0;
    transition: opacity 0.3s;
}

.cyber-button:hover {
    background: linear-gradient(45deg, transparent 5%, var(--neon-blue) 5%);
    box-shadow: 6px 0px 0px var(--neon-pink);
    text-shadow: 0 0 10px white;
    transform: translateY(-2px);
}

.cyber-button:hover::after {
    opacity: 1;
    transform: translate(-5px, -5px);
}

.cyber-button:active {
    transform: translateY(2px);
    box-shadow: 2px 0px 0px var(--neon-pink);
}

.icon-button {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--text-main);
    width: 50px;
    height: 50px;
    border-radius: 50%;
    font-size: 1.5rem;
    cursor: pointer;
    backdrop-filter: blur(10px);
    transition: all 0.3s ease;
    display: flex;
    justify-content: center;
    align-items: center;
}

.icon-button:hover {
    box-shadow: 0 0 15px var(--neon-blue);
    transform: scale(1.1);
}

.sound-toggle-container {
    position: absolute;
    bottom: 30px;
    right: 30px;
}

/* Glass Panels */
.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(15px);
    border: 1px solid var(--glass-border);
    border-radius: 15px;
    box-shadow: 0 0 30px rgba(0, 0, 0, 0.8), inset 0 0 20px rgba(0, 243, 255, 0.1);
}

.center-panel {
    width: 90%;
    max-width: 500px;
    height: auto;
    margin: auto;
    padding: 40px;
    justify-content: center;
    align-items: center;
    position: relative;
    top: 50%;
    transform: translateY(-50%);
    display: flex;
}

/* Tutorial Screen */
#tutorial-screen {
    justify-content: center;
    align-items: center;
    background: rgba(0,0,0,0.85);
}

.section-title {
    font-size: 2.5rem;
    color: var(--neon-blue);
    text-shadow: 0 0 15px var(--neon-blue);
    margin-bottom: 30px;
}

.tutorial-content {
    display: flex;
    flex-direction: column;
    gap: 20px;
    margin-bottom: 40px;
    max-width: 400px;
    width: 90%;
}

.tut-step {
    display: flex;
    align-items: center;
    gap: 20px;
    background: rgba(255,255,255,0.05);
    padding: 15px;
    border-radius: 10px;
    border-left: 4px solid var(--neon-pink);
}

.tut-icon {
    font-size: 2rem;
}

.tut-step p {
    font-size: 1.2rem;
    color: var(--text-dim);
}

/* Game HUD */
#game-hud {
    pointer-events: none;
    padding: 20px;
    justify-content: space-between;
}

.top-hud {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}

.health-container {
    width: 30%;
    max-width: 300px;
}

.health-label {
    font-size: 1rem;
    font-weight: 700;
    color: var(--neon-blue);
    margin-bottom: 5px;
    letter-spacing: 2px;
}

.health-bar-bg {
    width: 100%;
    height: 15px;
    background: rgba(255, 0, 0, 0.2);
    border: 1px solid var(--danger);
    border-radius: 10px;
    overflow: hidden;
    position: relative;
    box-shadow: 0 0 10px rgba(255, 51, 102, 0.3);
}

#health-bar-fill {
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, #ff0000, var(--danger));
    box-shadow: 0 0 15px var(--danger);
    transition: width 0.3s ease-out;
}

.wave-container, .score-container {
    text-align: center;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    padding: 10px 20px;
    border-radius: 8px;
    backdrop-filter: blur(5px);
}

.wave-container span, .score-container span {
    font-size: 0.9rem;
    color: var(--text-dim);
    letter-spacing: 1px;
}

#wave-display, #score-display {
    font-size: 1.8rem;
    font-weight: 700;
    font-family: 'Orbitron', sans-serif;
    color: var(--text-main);
    text-shadow: 0 0 10px rgba(255,255,255,0.5);
}

#wave-display { color: var(--neon-pink); text-shadow: 0 0 10px var(--neon-pink); }
#score-display { color: var(--neon-blue); text-shadow: 0 0 10px var(--neon-blue); }

.bottom-hud {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    pointer-events: auto;
    position: absolute;
    bottom: 20px;
    left: 20px;
    width: calc(100% - 40px);
}

.energy-container {
    display: flex;
    align-items: center;
    gap: 10px;
    background: rgba(0, 0, 0, 0.6);
    border: 1px solid var(--success);
    padding: 10px 20px;
    border-radius: 25px;
    box-shadow: 0 0 15px rgba(0, 255, 102, 0.3);
}

.energy-icon { font-size: 1.5rem; }

#energy-display, #upgrade-energy-display {
    font-size: 1.5rem;
    font-family: 'Orbitron', sans-serif;
    color: var(--success);
    font-weight: 700;
}

/* Upgrade Menu */
#upgrade-menu {
    width: 90%;
    max-width: 600px;
    height: auto;
    max-height: 80vh;
    margin: auto;
    position: relative;
    top: 50%;
    transform: translateY(-50%);
    padding: 30px;
    display: flex;
    flex-direction: column;
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    border-bottom: 1px solid var(--glass-border);
    padding-bottom: 15px;
}

.panel-header h2 {
    color: var(--neon-purple);
    text-shadow: 0 0 10px var(--neon-purple);
    font-size: 2rem;
}

.close-button {
    background: transparent;
    border: none;
    color: var(--text-dim);
    font-size: 2rem;
    cursor: pointer;
    transition: color 0.3s;
}

.close-button:hover { color: var(--danger); }

.upgrades-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
    overflow-y: auto;
    padding-right: 10px;
}

.upgrade-item {
    display: flex;
    align-items: center;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    padding: 15px;
    border-radius: 10px;
    transition: all 0.3s;
}

.upgrade-item:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--neon-blue);
    box-shadow: 0 0 15px rgba(0, 243, 255, 0.2);
}

.upgrade-item.special {
    border-color: var(--neon-pink);
    background: rgba(255, 0, 255, 0.05);
}

.upg-icon {
    font-size: 2.5rem;
    margin-right: 20px;
    width: 50px;
    text-align: center;
}

.upg-info {
    flex-grow: 1;
}

.upg-info h3 {
    font-size: 1.2rem;
    color: var(--text-main);
    margin-bottom: 5px;
}

.upg-level {
    font-size: 0.9rem;
    color: var(--neon-blue);
}

.btn-buy {
    background: rgba(0, 255, 102, 0.1);
    border: 1px solid var(--success);
    color: var(--success);
    padding: 10px 20px;
    border-radius: 5px;
    font-family: 'Orbitron', sans-serif;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 1.1rem;
}

.btn-buy:hover {
    background: var(--success);
    color: #000;
    box-shadow: 0 0 15px var(--success);
}

.btn-buy:disabled {
    background: rgba(255, 255, 255, 0.05);
    border-color: rgba(255, 255, 255, 0.2);
    color: rgba(255, 255, 255, 0.3);
    cursor: not-allowed;
    box-shadow: none;
}

.btn-buy.special {
    border-color: var(--neon-pink);
    color: var(--neon-pink);
}

.btn-buy.special:hover {
    background: var(--neon-pink);
    color: #fff;
    box-shadow: 0 0 15px var(--neon-pink);
}

/* Game Over Menu */
.text-danger {
    color: var(--danger);
    text-shadow: 0 0 20px var(--danger);
    font-size: 3rem;
    margin-bottom: 20px;
    text-align: center;
}

.stats-box {
    background: rgba(0,0,0,0.5);
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 30px;
    border-left: 5px solid var(--neon-blue);
    width: 100%;
}

.stats-box p {
    font-size: 1.5rem;
    margin: 10px 0;
    color: var(--text-dim);
}

.highlight {
    color: var(--neon-blue);
    font-weight: 700;
    font-family: 'Orbitron', sans-serif;
}

/* Wave Announcer */
#wave-announcer {
    position: absolute;
    top: 30%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    z-index: 20;
    pointer-events: none;
}

#announce-text {
    font-size: 5rem;
    color: var(--neon-pink);
    text-shadow: 0 0 30px var(--neon-pink), 0 0 60px rgba(255, 0, 255, 0.5);
    letter-spacing: 10px;
    animation: pulseWave 2s ease-in-out forwards;
    opacity: 0;
}

/* Animations */
@keyframes float {
    0% { transform: translateY(0px); }
    50% { transform: translateY(-15px); }
    100% { transform: translateY(0px); }
}

@keyframes glitch {
    0% { clip-path: polygon(0 0, 100% 0, 100% 45%, 0 45%); transform: translate(0); }
    20% { clip-path: polygon(0 55%, 100% 55%, 100% 100%, 0 100%); transform: translate(-2px, 2px); }
    40% { clip-path: polygon(0 0, 100% 0, 100% 45%, 0 45%); transform: translate(2px, -2px); }
    60% { clip-path: polygon(0 55%, 100% 55%, 100% 100%, 0 100%); transform: translate(-2px, -2px); }
    80% { clip-path: polygon(0 0, 100% 0, 100% 45%, 0 45%); transform: translate(2px, 2px); }
    100% { clip-path: polygon(0 55%, 100% 55%, 100% 100%, 0 100%); transform: translate(0); }
}

@keyframes pulseWave {
    0% { transform: scale(0.5); opacity: 0; }
    20% { transform: scale(1.2); opacity: 1; }
    80% { transform: scale(1); opacity: 1; }
    100% { transform: scale(1.5); opacity: 0; }
}

/* Responsive Styles */
@media (max-width: 768px) {
    .game-title { font-size: 2.5rem; }
    .game-subtitle { font-size: 1.5rem; letter-spacing: 10px; }
    .cyber-button { font-size: 1.2rem; padding: 12px 25px; }
    
    .top-hud { flex-wrap: wrap; gap: 10px; }
    .health-container { width: 100%; max-width: none; order: 3; margin-top: 10px; }
    #wave-display, #score-display { font-size: 1.2rem; }
    .wave-container, .score-container { padding: 5px 10px; }
    
    .bottom-hud { flex-direction: column; align-items: center; gap: 15px; }
    #btn-open-upgrades { width: 100%; text-align: center; }
    
    .panel-header h2 { font-size: 1.5rem; }
    .upg-icon { font-size: 2rem; margin-right: 10px; }
    .btn-buy { padding: 8px 15px; font-size: 1rem; }
    
    #announce-text { font-size: 3rem; }
}