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

body {
    font-family: 'Arial', sans-serif;
	background-image: 
    linear-gradient(to top, pink 0%, red 30%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

h1 {
    text-align: center;
    color: pink;
    margin-bottom: 30px;
    font-size: 2.5em;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    padding: 20px;
}

.door {
    position: relative;
    height: 150px;
    cursor: pointer;
    perspective: 1000px;
}

.door-front,
.door-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    transition: transform 0.6s;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    padding: 15px;
}

.door-front {
    background: linear-gradient(135deg, #c94b4b 0%, #4b134f 100%);
    box-shadow: 0 4px 8px rgba(0,0,0,0.3);
    border: 3px solid gold;
}

.day-number {
    font-size: 3em;
    color: white;
    font-weight: bold;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.door-back {
    background: white;
    transform: rotateY(180deg);
    overflow: hidden;
}

.door-back img {
    max-width: 100%;
    max-height: 70%;
    object-fit: cover;
    border-radius: 5px;
}

.door-back p {
    margin-top: 10px;
    font-size: 0.9em;
    text-align: center;
    color: #333;
}

.door.open .door-front {
    transform: rotateY(-180deg);
}

.door.open .door-back {
    transform: rotateY(0deg);
}

.door.locked {
    opacity: 0.5;
    cursor: not-allowed;
}

.door.locked:hover {
    transform: none;
}

/* Responsive Design */
@media (max-width: 768px) {
    .calendar-grid {
        grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
        gap: 10px;
    }
    
    .door {
        height: 120px;
    }
    
    h1 {
        font-size: 1.8em;
    }
}