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

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    touch-action: none;
    font-family: 'Comic Sans MS', 'Chalkboard SE', 'Comic Neue', sans-serif;
    background: linear-gradient(135deg, #dcfce7 0%, #bbf7d0 100%);
    cursor: crosshair;
}

body {
    display: flex;
    flex-direction: column;
    position: relative;
}

header {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 30px;
    z-index: 10;
}

.back-btn {
    background: white;
    padding: 12px 24px;
    border-radius: 50px;
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: bold;
    color: #16a34a;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    transition: transform 0.2s;
}

.back-btn:hover, .back-btn:active {
    transform: scale(1.05);
}

.score {
    background: white;
    padding: 12px 24px;
    border-radius: 50px;
    font-size: 1.8rem;
    font-weight: bold;
    color: #16a34a;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

#game-area {
    position: relative;
    width: 100%;
    height: 100%;
}

.balloon {
    position: absolute;
    font-size: clamp(5rem, 15vw, 10rem);
    cursor: pointer;
    user-select: none;
    transition: transform 0.1s;
    z-index: 5;
    line-height: 1;
    filter: drop-shadow(0 4px 8px rgba(0,0,0,0.15));
}

.balloon:hover, .balloon:active {
    transform: scale(1.1);
}

.balloon.popped {
    animation: pop 0.3s ease forwards;
}

#instruction {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 1.3rem;
    color: #15803d;
    font-weight: 500;
    text-align: center;
    pointer-events: none;
    padding: 0 20px;
}

.particle {
    position: absolute;
    border-radius: 50%;
    pointer-events: none;
    z-index: 4;
}

@keyframes pop {
    0% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.4); opacity: 0.8; }
    100% { transform: scale(0); opacity: 0; }
}

@keyframes explode {
    0% { transform: translate(0, 0) scale(1); opacity: 1; }
    100% { transform: translate(var(--vx), var(--vy)) scale(0); opacity: 0; }
}

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(-5deg); }
    50% { transform: translateY(-15px) rotate(5deg); }
}

.fullscreen-btn {
    font-size: 1.5rem;
    background: rgba(255,255,255,0.8);
    border: none;
    border-radius: 50%;
    width: 44px;
    height: 44px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    transition: transform 0.2s;
    flex-shrink: 0;
    text-decoration: none;
    color: inherit;
}
.fullscreen-btn:active {
    transform: scale(0.9);
}