/* Reset y variables */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --pink-start: #ff6fbf;
    --purple-end: #6b3cff;

    --text-color: #ffffff;
    --placeholder-color: rgba(255, 255, 255, 0.7);
    --border-radius: 12px;
    --padding: 12px 16px;

    --color-bg: #0a0f1a;
    --color-bg2: #0a0f1ab6;
    --color-button-bg: #1d3b56;
    --color-button-bg2: #1d3b569a;
}

/* Body con fondo estrellado */
body {
    color: var(--text-color);
    font-family: 'Poppins', sans-serif;

    background: radial-gradient(circle at top center, var(--color-button-bg) 2%, var(--color-bg) 100%),
                url('cielo-estrellado.png');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    background-blend-mode: overlay;

    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;

    /* Animación de estrellas */
    animation: estrellas 120s linear infinite;
}

/* Animación estrellas */
@keyframes estrellas {
    0% { background-position: 0 0; }
    100% { background-position: 0 1000px; }
}

/* Contenedor principal */
main {
    width: 90%;
    max-width: 420px;
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

/* Imagen de luna */
.img-luna {
    width: 120px;
    margin-bottom: 15px;
    filter: drop-shadow(0 0 15px var(--text-color));
    z-index: 1;
}

/* Resultados */
.resultados {
    margin-bottom: 20px;
}

.resultado {
    font-size: 1.8rem;
    color: var(--pink-start);
}

/* Input de fecha */
.input-edad {
    width: 100%;
    max-width: 100%;
    background: linear-gradient(to left, var(--pink-start), var(--purple-end));
    border: none;
    border-radius: var(--border-radius);
    padding: var(--padding);
    font-size: 1rem;
    color: var(--text-color);
    outline: none;
    box-shadow: 0 2px 8px rgba(0,0,0,0.18);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
    animation: brillar 2s infinite alternate;
    margin-bottom: 15px;
}

.input-edad::placeholder {
    color: var(--placeholder-color);
}

/* Botón */
.btn {
    width: 100%;
    max-width: 100%;
    background: linear-gradient(to left, var(--color-button-bg), var(--color-bg));
    border: none;
    border-radius: var(--border-radius);
    padding: var(--padding);
    font-size: 1rem;
    color: var(--text-color);
    cursor: pointer;
    filter: drop-shadow(0 4px 8px rgba(0,0,0,0.25));
    transition: transform 0.25s ease, filter 0.25s ease, background 0.25s ease, border-color 0.25s ease;
    border-right: 3px solid var(--color-bg);
    border-bottom: 3px solid var(--color-bg);
    outline: 3px solid var(--color-button-bg);
}

.btn:hover {
    background: linear-gradient(to left, var(--color-button-bg2), var(--color-bg2));
    border-right: 3px solid var(--color-button-bg);
    border-bottom: 3px solid var(--color-button-bg2);
    transform: translateY(-4px) scale(1.03);
    filter: drop-shadow(0 10px 16px rgba(0,0,0,0.35));
}

.btn:active {
    transform: translateY(2px) scale(0.98);
    filter: drop-shadow(0 3px 6px rgba(0,0,0,0.2));
}

/* Animación de brillo input */
@keyframes brillar {
    0%, 100% {
        filter: drop-shadow(0 0 5px var(--purple-end));
    }
    50% {
        filter: drop-shadow(0 0 10px var(--purple-end));
    }
}

/* Ajustes para pantallas pequeñas */
@media (max-width: 480px) {
    .img-luna {
        width: 100px;
    }
    .resultado {
        font-size: 1.5rem;
    }
    .input-edad, .btn {
        font-size: 0.9rem;
        padding: 10px 14px;
    }
    main {
        padding: 15px;
    }
}