body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f4f4;
    color: #222;
}

header {
    background: #1f4e79;
    color: white;
    text-align: center;
    padding: 45px 20px;
}

header h1 {
    margin: 0 0 12px;
    font-size: 38px;
}

header p {
    margin: 0;
    font-size: 18px;
}

nav {
    background: #163b5c;
    text-align: center;
    padding: 16px;
}

nav a {
    color: white;
    text-decoration: none;
    margin: 0 18px;
    font-size: 18px;
    font-weight: bold;
}

nav a:hover {
    color: #ffd966;
}

main {
    max-width: 1220px;
    margin: 30px auto;
    background: white;
    padding: 40px;
    box-sizing: border-box;
}

.einleitung {
    margin-bottom: 30px;
}

.einleitung h2 {
    margin-top: 0;
    color: #1f4e79;
    font-size: 32px;
}

.einleitung p {
    font-size: 18px;
    line-height: 1.6;
}

.infothek-bereich {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 25px;
}

.themenliste {
    background: #eef4f8;
    border: 1px solid #c6d5e2;
    border-radius: 12px;
    padding: 20px;
    align-self: start;
    position: sticky;
    top: 20px;
    max-height: calc(100vh - 40px);
    overflow-y: auto;
    box-sizing: border-box;
}

.themenliste h3 {
    margin: 0 0 18px;
    color: #1f4e79;
    font-size: 24px;
}

.thema-button {
    width: 100%;
    display: block;
    margin-bottom: 10px;
    padding: 13px 14px;
    border: 1px solid #a8bdcc;
    border-radius: 7px;
    background: white;
    color: #222;
    text-align: left;
    font-size: 15px;
    font-weight: bold;
    line-height: 1.35;
    cursor: pointer;
    transition: 0.25s;
}

.thema-button:hover {
    background: #dfeef7;
}

.thema-button.aktiv {
    background: #1f4e79;
    color: white;
    border-color: #1f4e79;
}

.themenanzeige {
    background: #e8f5df;
    border: 1px solid #bad4aa;
    border-radius: 12px;
    padding: 28px;
    position: sticky;
    top: 20px;
    align-self: start;
}

.themenanzeige h2 {
    margin: 0 0 28px;
    padding-bottom: 15px;
    border-bottom: 2px solid #6e9c78;
    color: #173f2d;
    font-size: 29px;
    text-align: center;
}

.themeninhalt {
    display: grid;
    grid-template-columns: 175px 1fr 250px;
    gap: 22px;
    align-items: start;
}

.bezeichnungen,
.aussagen {
    display: grid;
    grid-template-rows: repeat(5, minmax(58px, auto));
    gap: 10px;
}

.bezeichnung {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 58px;
    padding: 8px 10px;
    box-sizing: border-box;
    border: 2px solid #4b5a4b;
    background: rgba(255, 255, 255, 0.4);
    text-align: center;
    font-weight: bold;
}

.bezeichnung.kern {
    color: #d00000;
}

.aussage {
    display: flex;
    align-items: center;
    min-height: 58px;
    padding: 8px 10px;
    box-sizing: border-box;
    font-size: 16px;
    line-height: 1.45;
}

.aussage.kern {
    font-weight: bold;
}

.bildbereich {
    text-align: center;
}

.themenbild,
.bild-platzhalter {
    width: 100%;
    height: 300px;
    border-radius: 7px;
    box-sizing: border-box;
}

.themenbild {
    object-fit: cover;
    display: block;
    box-shadow: 0 5px 14px rgba(0, 0, 0, 0.18);
}

.bild-platzhalter {
    display: none;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: #d8e5d1;
    color: #435343;
    font-weight: bold;
}

.mehr-infos {
    display: inline-block;
    margin-top: 18px;
    padding: 12px 25px;
    border-radius: 6px;
    background: #12618a;
    color: white;
    text-decoration: none;
    font-size: 17px;
    font-weight: bold;
}

.mehr-infos:hover {
    background: #0c4867;
}

footer {
    text-align: center;
    padding: 25px;
    background: #163b5c;
    color: white;
    margin-top: 35px;
}

@media (max-width: 1000px) {
    .infothek-bereich {
        grid-template-columns: 1fr;
    }

    .themenliste,
    .themenanzeige {
        position: static;
        max-height: none;
        overflow: visible;
    }

    .themenliste {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    .themenliste h3 {
        grid-column: 1 / -1;
    }

    .thema-button {
        margin-bottom: 0;
    }

    .themeninhalt {
        grid-template-columns: 160px 1fr;
    }

    .bildbereich {
        grid-column: 1 / -1;
        max-width: 450px;
        width: 100%;
        margin: 15px auto 0;
    }
}

@media (max-width: 650px) {
    nav a {
        display: block;
        margin: 12px 0;
    }

    main {
        margin: 15px;
        padding: 22px;
    }

    header h1 {
        font-size: 30px;
    }

    .themenliste {
        grid-template-columns: 1fr;
    }

    .themeninhalt,
    .bezeichnungen,
    .aussagen {
        display: block;
    }

    .bezeichnung {
        margin-top: 18px;
        min-height: 44px;
    }

    .aussage {
        min-height: auto;
        padding: 12px 4px;
    }

    .bildbereich {
        margin-top: 25px;
    }

    .themenbild,
    .bild-platzhalter {
        height: 250px;
    }
}