* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

body {
    background-color: #E6EEFF;
    min-height: 100vh;
    padding: 2rem;
}

.container {
    max-width: 100%;
    min-height: 100vh;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 2vh;
    gap: 2rem;
}

h1 {
    text-align: center;
    color: #333;
    font-size: min(5.5rem, 8vw);
    margin-bottom: 3vh;
    font-weight: 300;
}

.app-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: min(50px, 5vw);
    justify-items: center;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
    width: 100%;
    padding: 1rem;
}

.app-card {
    position: relative;
    width: min(300px, 90vw);
    height: min(400px, 70vh);
    perspective: 1000px;
    cursor: pointer;
    margin: 1rem 0;
}

.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.8s;
    transform-style: preserve-3d;
}

.app-card:hover .card-inner {
    transform: none;
}

@media (min-width: 1024px) {
    .app-card:hover .card-inner {
        transform: rotateY(180deg);
    }
}

@media (max-width: 1023px) {
    .app-card .card-inner.flipped {
        transform: rotateY(180deg);
    }
}

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    background: white;
    border-radius: 16px;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.card-back {
    transform: rotateY(180deg);
    padding: 2rem;
    background: #333;
    color: white;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    text-align: center;
}

.card-back h3 {
    font-size: min(1.5rem, 4vw);
    margin-bottom: 1.5rem;
    color: white;
}

.card-back p {
    font-size: min(1rem, 2.8vw);
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.card-back ul {
    list-style: none;
    text-align: center;
    margin: 1rem 0;
    width: 100%;
}

.card-back li {
    margin: 0.8rem 0;
    font-size: min(0.9rem, 2.5vw);
}

.card-content {
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.app-icon {
    width: min(120px, 20vw);
    height: min(120px, 20vw);
    margin-bottom: min(2rem, 3vh);
}

.heartivia-icon {
    width: min(120px, 20vw);
    height: min(110px, 18vw);
}

.app-name {
    font-size: min(1.5rem, 4vw);
    font-weight: 600;
    margin-bottom: min(1rem, 2vh);
    color: #333;
}

.app-description {
    font-size: min(1.1rem, 3vw);
    color: #666;
    text-align: center;
    margin-bottom: min(2rem, 3vh);
}

.get-app-btn {
    background: #333;
    color: white;
    border: none;
    padding: min(0.5rem, 1vh) min(2rem, 3vw);
    border-radius: 20px;
    cursor: pointer;
    font-weight: 500;
    transition: background-color 0.3s;
    font-size: min(1rem, 2.5vw);
    text-decoration: none;
    display: inline-block;
}

.get-app-btn:hover {
    background: #444;
}

.get-app-btn.white {
    background: white;
    color: #333;
}

.get-app-btn.white:hover {
    background: #f0f0f0;
}

.flip-icon {
    position: absolute;
    top: 1rem;
    right: 1rem;
    color: #666;
    font-size: 1.2rem;
    animation: bounce 2s infinite;
    opacity: 0.7;
}

@keyframes bounce {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-3px);
    }
}

.tap-icon {
    display: none;
}

@media (max-width: 1023px) {
    .flip-icon {
        display: none;
    }
    .tap-icon {
        display: block;
    }
}

.card-back .flip-icon,
.card-back .tap-icon {
    display: none;
}