:root {
    --background-color: #0c0c1e;
    --primary-neon: #00ffff;
    --secondary-neon: #ff00ff;
    --text-color: #f0f0f0;
    --grid-line-color: rgba(0, 255, 255, 0.1);
    --grid-highlight-color: rgba(0, 255, 255, 0.7);
    --tower-basic: #00ffff;
    --tower-tesla: #ff00ff;
    --creep-color: #ffcc00;
    --projectile-color: #ffffff;
    --font-family: 'Courier New', Courier, monospace;
}

body {
    background-color: var(--background-color);
    background-image: url('background.png');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    color: var(--text-color);
    font-family: var(--font-family);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    margin: 0;
    padding-top: 20px;
    overflow: hidden;
}

#game-container {
    display: grid;
    grid-template-columns: auto 1fr;
    grid-template-rows: auto 1fr;
    grid-template-areas:
        "top-bar side-bar"
        "canvas side-bar";
    gap: 15px;
    border: 1px solid var(--primary-neon);
    box-shadow: 0 0 15px var(--primary-neon);
    padding: 15px;
    background-color: rgba(12, 12, 30, 0.8);
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px); /* Safari 9+ */
    /* For Firefox 103+ */
    @-moz-document url-prefix() {
        backdrop-filter: blur(5px);
    }
}

#top-bar {
    grid-area: top-bar;
    display: flex;
    justify-content: space-around;
    background-color: rgba(0,0,0,0.5);
    padding: 10px;
    border-radius: 5px;
    border: 1px solid var(--secondary-neon);
    box-shadow: 0 0 10px var(--secondary-neon) inset;
}

.stat-box {
    text-align: center;
}

.stat-label {
    font-size: 0.8em;
    color: var(--primary-neon);
    text-shadow: 0 0 5px var(--primary-neon);
}

.stat-value {
    font-size: 1.2em;
    font-weight: bold;
    color: var(--text-color);
}

#start-wave-box {
    margin: 16px 0;
    text-align: center;
}

#start-wave-btn {
    width: 90%;
    padding: 10px 0;
    font-size: 1.1em;
}

#game-canvas {
    grid-area: canvas;
    border: 1px solid var(--primary-neon);
    box-shadow: 0 0 10px var(--primary-neon);
}

#game-canvas.sell-mode {
    cursor: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='32' height='32' style='font-size: 24px;'><text y='24' fill='%23ff0000'>💲</text></svg>") 16 16, auto;
}

#side-bar {
    grid-area: side-bar;
    width: 200px;
    background-color: rgba(0,0,0,0.5);
    padding: 15px;
    border-radius: 5px;
    border: 1px solid var(--secondary-neon);
    box-shadow: 0 0 10px var(--secondary-neon) inset;
}

.sidebar-title {
    text-align: center;
    color: var(--secondary-neon);
    text-shadow: 0 0 8px var(--secondary-neon);
    margin-top: 0;
    margin-bottom: 10px;
}

.sidebar-content {
    margin-bottom: 20px;
}

.sidebar-content h4 {
    color: var(--primary-neon);
    text-shadow: 0 0 5px var(--primary-neon);
    margin-top: 0;
    margin-bottom: 10px;
}

#sell-tower-btn.active {
    background-color: var(--secondary-neon);
    color: var(--background-color);
    box-shadow: 0 0 10px var(--secondary-neon);
}

.unlock-button, .spell-button, #sell-tower-btn, #initial-start-btn {
    width: 100%;
    padding: 8px;
    margin-bottom: 10px;
    font-size: 0.9em;
    text-align: left;
}

.unlock-button .cost, .spell-button .cost {
    float: right;
    font-weight: bold;
}

.menu {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
}

.menu-content {
    background-color: var(--background-color);
    padding: 30px;
    border-radius: 10px;
    border: 2px solid var(--primary-neon);
    box-shadow: 0 0 20px var(--primary-neon);
    text-align: center;
}

.menu-content h2, .menu-content h3 {
    color: var(--primary-neon);
    text-shadow: 0 0 8px var(--primary-neon);
    margin-top: 0;
}

#tower-options {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
}

.tower-option {
    border: 1px solid var(--secondary-neon);
    padding: 10px;
    cursor: pointer;
    transition: all 0.2s ease-in-out;
    background-color: rgba(12, 12, 30, 0.9);
}

.tower-option:hover {
    background-color: var(--secondary-neon);
    color: var(--background-color);
    box-shadow: 0 0 10px var(--secondary-neon);
}
.tower-option.disabled {
    border-color: #555;
    color: #555;
    cursor: not-allowed;
}
.tower-option.disabled:hover {
    background-color: rgba(12, 12, 30, 0.9);
    box-shadow: none;
}

.tower-cost {
    font-size: 0.8em;
    margin-top: 5px;
}

button {
    background-color: transparent;
    border: 1px solid var(--primary-neon);
    color: var(--primary-neon);
    padding: 10px 20px;
    cursor: pointer;
    font-family: var(--font-family);
    transition: all 0.2s ease-in-out;
    text-shadow: 0 0 5px var(--primary-neon);
}

button:hover {
    background-color: var(--primary-neon);
    color: var(--background-color);
    box-shadow: 0 0 10px var(--primary-neon);
}

button:disabled {
    border-color: #555;
    color: #555;
    cursor: not-allowed;
    text-shadow: none;
}
button:disabled:hover {
    background-color: transparent;
    box-shadow: none;
}

#wave-countdown {
    margin: 18px 0 0 0;
    padding: 10px;
    background: rgba(20,20,40,0.85);
    border-radius: 8px;
    text-align: center;
    font-size: 1.2em;
    color: #fff600;
    box-shadow: 0 0 8px #fff60044;
}