body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    font-family: 'Montserrat', sans-serif;
    transition: background-image 0.6s ease-in-out; /* Etwas langsamerer Übergang für Atmosphäre */
}

/* === THEME 1: STANDARD (Ozean/Dunkel) === */
body {
    background-color: #000;
    background-image: linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.4)), url('https://images.unsplash.com/photo-1549880181-56a44cf4a9a5');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
}

/* === THEME 2: TANNENWALD (Dunkler Nadelwald) === */
body.theme-autumn {
    /* Stimmungsvoller Tannenwald im Nebel */
    background-image: linear-gradient(rgba(10, 20, 10, 0.3), rgba(10, 20, 10, 0.3)), url('https://images.unsplash.com/photo-1511497584788-876760111969');
}

/* === THEME 3: WINTERBERGE (Schnee & Berge) === */
body.theme-winter {
    /* Verschneite Bergkette */
    background-image: linear-gradient(rgba(0, 10, 25, 0.3), rgba(0, 10, 25, 0.3)), url('https://images.unsplash.com/photo-1491002052546-bf38f186af56');
}


/* === NEUE BUTTONS (Größer & Nummeriert) === */
.theme-switch-container {
    position: absolute;
    top: 30px;
    right: 30px;
    z-index: 20;
    display: flex;
    gap: 15px;
}

.theme-btn {
    width: 40px;        /* Deutlich größer */
    height: 40px;       /* Deutlich größer */
    border-radius: 50%; /* Rund bleiben */
    border: 2px solid rgba(255, 255, 255, 0.7);
    background-color: rgba(0, 0, 0, 0.3); /* Dunklerer Hintergrund für bessere Lesbarkeit der Zahl */
    color: white;       /* Textfarbe Weiß */
    font-family: 'Montserrat', sans-serif;
    font-weight: 700;   /* Fette Zahl */
    font-size: 16px;    /* Lesbare Größe */
    
    cursor: pointer;
    transition: all 0.3s ease;
    outline: none;
    
    /* Zahl zentrieren */
    display: flex;
    justify-content: center;
    align-items: center;
}

/* Hover Effekt */
.theme-btn:hover {
    transform: scale(1.1); /* Leichtes Vergrößern */
    background-color: rgba(255, 255, 255, 1);
    color: #000; /* Zahl wird schwarz beim Hover */
    border-color: #fff;
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.5);
}

/* Aktiver Button (ausgewählt) */
.theme-btn.active {
    background-color: #fff;
    color: #000;
    border-color: #fff;
    transform: scale(1.1);
}


/* === LAYOUT (Rest bleibt gleich) === */
.container {
    position: relative;
    z-index: 2;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100vh;
    text-align: center;
    color: white;
    padding: 20px;
    box-sizing: border-box;
}

header h1 {
    font-size: 4rem;
    margin-bottom: 25px;
    text-shadow: 2px 2px 8px rgba(0,0,0,0.8);
    font-weight: 700;
}

main p {
    font-size: 1.1rem;
    max-width: 550px; 
    line-height: 1.7;
    text-shadow: 2px 2px 6px rgba(0,0,0,0.9);
}

footer {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 3;
}

footer a {
    color: white;
    text-decoration: none;
    font-size: 0.9rem;
    text-shadow: 1px 1px 4px rgba(0,0,0,0.8);
    transition: opacity 0.3s;
}

footer a:hover {
    opacity: 0.8;
}

.popup {
    display: none;
    position: fixed;
    z-index: 100;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.7);
}

.popup-content {
    background-color: #fefefe;
    color: #333;
    margin: 15% auto;
    padding: 20px;
    border: 1px solid #888;
    width: 80%;
    max-width: 500px;
    position: relative;
    border-radius: 5px;
    text-align: left;
}

.close-button {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
}

.close-button:hover,
.close-button:focus {
    color: black;
    text-decoration: none;
    cursor: pointer;
}