:root {
    /* Colores inspirados en una estética romántica y limpia */
    --primary-red: #ff4d6d;
    --envelope-bg: #ff85a1;
    --envelope-dark: #ff758f;
    --letter-bg: #ffffff;
    --page-bg: #ffe5ec;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: var(--page-bg);
    font-family: 'Arial', sans-serif;
}

.container {
    position: relative;
}

.envelope-wrapper {
    position: relative;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.envelope-wrapper:hover {
    transform: scale(1.05);
}

.envelope {
    position: relative;
    width: 320px;
    height: 220px;
    background-color: var(--envelope-bg);
    border-radius: 0 0 10px 10px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

/* Solapa del sobre */
.envelope::before {
    content: "";
    position: absolute;
    top: 0;
    z-index: 3;
    border-top: 130px solid var(--envelope-dark);
    border-left: 160px solid transparent;
    border-right: 160px solid transparent;
    transform-origin: top;
    transition: transform 0.5s ease-in-out;
}

.letter {
    position: absolute;
    bottom: 10px;
    left: 10px;
    width: 300px;
    height: 200px; /* Tamaño base de la carta */
    background: var(--letter-bg);
    border-radius: 8px;
    padding: 15px;
    box-sizing: border-box;
    transition: transform 0.6s ease-in-out;
    z-index: 2;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.text {
    text-align: center;
    color: #444;
}

.text p {
    font-size: 14px;
    margin: 10px 0 0 0;
}

/* Animaciones cuando se abre (clase .open) */
.envelope-wrapper.open .envelope::before {
    transform: rotateX(180deg);
    z-index: 1; /* Pasa atrás para que no tape la carta */
}

.envelope-wrapper.open .letter {
    transform: translateY(-140px); /* Sube la carta para mostrar Spotify */
    z-index: 4;
}

/* El Corazón */
.heart {
    position: absolute;
    top: 40%;
    left: 50%;
    width: 30px;
    height: 30px;
    background-color: var(--primary-red);
    transform: translate(-50%, -50%) rotate(45deg);
    z-index: 5;
    transition: opacity 0.4s ease;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.heart::before, .heart::after {
    content: "";
    position: absolute;
    width: 30px;
    height: 30px;
    background-color: var(--primary-red);
    border-radius: 50%;
}

.heart::before { left: -15px; }
.heart::after { top: -15px; }

.envelope-wrapper.open .heart {
    opacity: 0;
    pointer-events: none;
}