body {
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #87CEEB;
    /* 하늘색 배경 */
    font-family: 'Malgun Gothic', sans-serif;
    color: white;
}

#game-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    pointer-events: none;
    z-index: 10;
}

#hud {
    position: absolute;
    top: 20px;
    width: 100%;
    display: flex;
    justify-content: space-around;
    font-size: 30px;
    font-weight: bold;
    text-shadow: 2px 2px 4px #000;
}

#timer-box {
    color: #ffd54f;
    font-size: 50px;
}

#survivor-box {
    color: #ef5350;
}

/* Screens */
.screen {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 20;
    text-align: center;
    pointer-events: auto;
}

.screen.active {
    display: flex;
}

.screen h1 {
    font-size: 50px;
    margin-bottom: 20px;
    color: #ff9800;
    text-shadow: 0 0 10px #ff5722;
}

.screen p {
    font-size: 20px;
    margin-bottom: 30px;
    line-height: 1.5;
}

.btn {
    padding: 15px 30px;
    font-size: 24px;
    font-family: inherit;
    font-weight: bold;
    background: #4caf50;
    color: white;
    border: 3px solid white;
    border-radius: 10px;
    cursor: pointer;
    margin: 10px;
    transition: transform 0.1s, background 0.2s;
    pointer-events: auto;
}

.btn:hover {
    background: #388e3c;
    transform: scale(1.05);
}

.btn:active {
    transform: scale(0.95);
}

#announcement {
    position: absolute;
    top: 40%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 60px;
    color: white;
    text-shadow: 2px 2px 0px black, 0 0 20px yellow;
    z-index: 15;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s;
}