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

body {
    font-family: 'Arial', sans-serif;
    background-color: #1a1a1a;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: #ffffff;
}

#gameContainer {
    position: relative;
    /* Dimensions are now controlled by canvas size which matches constants */
    border: 3px solid #00ff00;
    background-color: #000000;
    box-shadow: 0 0 20px rgba(0, 255, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
}

#gameCanvas {
    display: block;
    width: 100%;
    height: 100%;
    background-color: #000000;
    image-rendering: pixelated;
    image-rendering: crisp-edges;
}

#hud {
    position: absolute;
    top: 10px;
    left: 10px;
    right: 10px;
    font-size: 14px;
    color: #00ff00;
    font-family: 'Courier New', monospace;
}

/* Upgrade UI Styles (will be expanded) */
.upgrade-screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.upgrade-options {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
    max-width: 700px;
}

.upgrade-card {
    border: 2px solid #00ff00;
    padding: 20px;
    width: 200px;
    text-align: center;
    cursor: pointer;
    background-color: rgba(0, 20, 0, 0.5);
    transition: all 0.2s;
}

.upgrade-card:hover {
    background-color: rgba(0, 255, 0, 0.1);
    box-shadow: 0 0 10px rgba(0, 255, 0, 0.5);
}

.upgrade-card h3 {
    color: #00ff00;
    margin-bottom: 10px;
}

.upgrade-card p {
    color: #aaffaa;
    font-size: 12px;
}

/* Pause Menu Styles */
.pause-menu {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: rgba(0, 0, 0, 0.95);
    border: 2px solid #00ff00;
    padding: 40px;
    text-align: center;
    z-index: 2000;
}

.pause-menu h2 {
    color: #00ff00;
    margin-bottom: 30px;
    font-size: 32px;
}

.menu-button {
    display: block;
    width: 200px;
    margin: 15px auto;
    padding: 10px;
    background-color: #001a00;
    border: 2px solid #00ff00;
    color: #00ff00;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.2s;
}

.menu-button:hover {
    background-color: #00ff00;
    color: #000000;
}

/* Main Menu Styles */
#mainMenu {
    position: absolute;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #000000, #001a00);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 3000;
}

#mainMenu h1 {
    color: #00ff00;
    font-size: 48px;
    margin-bottom: 20px;
    text-shadow: 0 0 20px rgba(0, 255, 0, 0.5);
}

#mainMenu p {
    color: #aaffaa;
    font-size: 16px;
    margin-bottom: 40px;
}

.start-button {
    padding: 15px 40px;
    font-size: 24px;
    background-color: #00ff00;
    color: #000000;
    border: none;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: bold;
}

.start-button:hover {
    background-color: #00cccc;
    transform: scale(1.05);
}