body {
    overflow: hidden;
}

.interface-content {
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100vh;
    width: 100vw;
}

.fullscreen-btn {
    position: absolute;
    top: 2rem;
    right: 2rem;
    width: 80px;
    height: 80px;
    font-size: 2.5rem;
    z-index: 10;
}

.fullscreen-btn:active {
    position: absolute;
    top: 2rem;
}

.header {
    position: absolute;
    top: 2rem;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(to bottom, #f9f9f9 5%, #e9e9e9 100%);
    border: 2px solid #dcdcdc;
    border-radius: 20px;
    padding: 1.5rem 4rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.header h1 {
    font-family: Arial, sans-serif;
    font-size: 4rem;
    font-weight: bold;
    color: #333333;
    text-shadow: 0px 2px 0px #ffffff;
    margin: 0;
}

.countdown {
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(to bottom, #f9f9f9 5%, #e9e9e9 100%);
    border: 3px solid #dcdcdc;
    border-radius: 30px;
    padding: 3rem 6rem;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
    min-width: 60vw;
}

.countdown h2 {
    font-family: Arial, sans-serif;
    font-size: 15vw;
    font-weight: bold;
    color: #333333;
    text-shadow: 0px 4px 0px #ffffff;
    margin: 0;
    line-height: 1;
}

@media (min-width: 1920px) {
    .header h1 {
        font-size: 5vw;
    }
    
    .countdown h2 {
        font-size: 18vw;
    }
    
    .fullscreen-btn {
        width: 100px;
        height: 100px;
        font-size: 3rem;
    }
}

@media (min-width: 3840px) {
    .header h1 {
        font-size: 4vw;
    }
    
    .countdown h2 {
        font-size: 16vw;
    }
}