body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: #27ae60;
    font-family: 'Courier New', Courier, monospace;
    color: white;
}

#game-container {
    width: 100vw;
    height: 100vh;
    position: relative;
}

canvas {
    display: block;
    background: #2ecc71;
}

#ui span, #ui b {
    pointer-events: none;
}

#ui button:hover {
    background: #d35400;
}

#ui {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: auto;
    z-index: 10;
    background: none;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    padding: 15px 25px;
    box-sizing: border-box;
    pointer-events: none;
}

#stats {
    display: flex;
    gap: 25px;
    font-size: 1.4rem;
    font-weight: bold;
    color: #ffffff;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.8);
    pointer-events: none;
}

#ui button {
    pointer-events: auto;
    box-shadow: 2px 2px 10px rgba(0,0,0,0.3);
}

#back-to-menu {
    background: #c0392b !important;
    border: 2px solid #a93226 !important;
    color: white;
}

#difficulty-settings {
    display: flex;
    gap: 8px;
    pointer-events: auto;
}

.diffBtn {
    padding: 8px 15px;
    cursor: pointer;
    background: #34495e;
    border: 2px solid #2c3e50;
    color: white;
    font-family: 'Courier New', Courier, monospace;
    font-weight: bold;
    transition: 0.2s;
    pointer-events: auto;
}

.diffBtn:hover {
    background: #7f8c8d;
}

.diffBtn.active {
    background: #27ae60;
    border-color: #2ecc71;
    box-shadow: 0 0 10px rgba(46, 204, 113, 0.5);
}

.waveBtnStyle {
    padding: 15px 30px;
    cursor: pointer;
    background: #e67e22;
    border: 3px solid #d35400;
    color: white;
    font-weight: bold;
    font-family: 'Courier New', monospace;
    text-transform: uppercase;
    font-size: 20px;
    pointer-events: auto;
}

.waveBtnStyle:hover {
    background: #d35400;
}

#main-menu {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #2c3e50;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 100;
    text-align: center;
}

#main-menu h1 {
    font-size: 4rem;
    margin-bottom: 20px;
    text-shadow: 4px 4px #27ae60;
}

.level-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 15px;
    max-width: 600px;
}

.level-btn {
    width: 80px;
    height: 80px;
    background: #e67e22;
    border: 4px solid #d35400;
    color: white;
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: 0.2s;
}

.level-btn:hover {
    background: #d35400;
    transform: scale(1.1);
}

.level-btn.locked {
    background: #7f8c8d;
    border-color: #34495e;
    cursor: not-allowed;
    opacity: 0.5;
    transform: none;
}

#waveBtn {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 20;
}