html, body {
    max-width: 100vw;
    overflow-x: hidden;
}
/* Responsive Design für mobile Geräte */
@media (max-width: 900px) {
    main, #courseContent {
        max-width: 98vw;
        padding: 1rem;
        margin: 1rem auto;
    }
    .main-nav, .nav-left, .nav-right {
        flex-direction: column;
        gap: 0.7rem;
        align-items: flex-start;
    }
    h1 {
        font-size: 2rem;
    }
    .video-list {
        gap: 1rem;
        flex-direction: column;
        align-items: center;
        display: flex;
    }
    .video-card, .card, .card-large, .big-card {
        width: 98vw !important;
        max-width: 700px !important;
        min-width: 0 !important;
        box-sizing: border-box;
        padding: 0.2rem 0.5rem !important;
        margin: 0.7rem auto 0.7rem auto !important;
        display: flex;
        flex-direction: column;
        align-items: center;
        word-break: break-word;
        font-size: 1.05rem !important;
    }
    .big-card h2, .big-card h3 {
        font-size: 1.05rem !important;
        word-break: break-word;
        white-space: normal !important;
        overflow-wrap: break-word !important;
        line-height: 1.2 !important;
    }
    .big-card ul, .big-card p, .big-card li {
        word-break: break-word;
        font-size: 1.01rem !important;
        line-height: 1.5 !important;
    }
    video {
        max-width: 100vw;
        height: auto;
    }
}

@media (max-width: 600px) {
    body {
        font-size: 1rem;
    }
    h1 {
        font-size: 1.3rem;
    }
    h2 {
        font-size: 1.1rem;
    }
    .main-nav, .nav-left, .nav-right {
        flex-direction: column;
        gap: 0.5rem;
        align-items: flex-start;
    }
    .video-card, .card, .card-large, .big-card {
        width: 96vw !important;
        max-width: 98vw !important;
        min-width: 0 !important;
        box-sizing: border-box;
        padding: 0.2rem;
        margin: 1.2rem auto 1.2rem auto !important;
        display: flex;
        flex-direction: column;
        align-items: center;
    }
    video {
        max-width: 100vw;
        height: auto;
    }
    #courseContent, main {
        padding: 0.5rem;
        border-radius: 8px;
    }
}
/* Navigation links links/rechts gruppieren und vertikal zentrieren */
.main-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 2rem;
    padding: 1.2rem 0 0.5rem 0;
    max-width: 1200px;
    margin: 0 auto;
}
.nav-left, .nav-right {
    display: flex;
    align-items: center;
    gap: 1.2rem;
}
#authLinks a, #logoutLink {
    font-weight: 700;
    font-family: 'Montserrat', Arial, sans-serif;
    font-size: 1.1rem;
    margin-right: 0.5rem;
    text-decoration: none;
    color: #222;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: background 0.18s, color 0.18s;
}
#authLinks a:last-child {
    margin-right: 0;
}
#logoutLink {
    margin-right: 0;
    cursor: pointer;
}
.nav-right a {
    font-weight: 600;
    font-family: 'Montserrat', Arial, sans-serif;
    font-size: 1.1rem;
    text-decoration: none;
    color: #222;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: background 0.18s, color 0.18s;
}
.nav-right a.active, .nav-right a:hover {
    background: #111;
    color: #fff;
}
#authLinks a:hover, #logoutLink:hover {
    background: #111;
    color: #fff;
}
.card-shuffle {
    background: rgba(255,255,255,0.45);
    border-radius: 32px;
    box-shadow: 0 8px 40px rgba(60,60,90,0.10);
    padding: 2.5rem 1.5rem;
    margin: 2.5rem auto;
    max-width: 1300px;
    backdrop-filter: blur(16px) saturate(1.2);
    -webkit-backdrop-filter: blur(16px) saturate(1.2);
}
/* Transparenter, blurriger Container für Kurs-Inhalt */
#courseContent {
    background: rgba(255,255,255,0.45);
    border-radius: 32px;
    box-shadow: 0 8px 40px rgba(60,60,90,0.10);
    padding: 2.5rem 1.5rem;
    margin: 2.5rem auto;
    max-width: 1100px;
    backdrop-filter: blur(16px) saturate(1.2);
    -webkit-backdrop-filter: blur(16px) saturate(1.2);
}
.card-shuffle {
    z-index: 0;
}
body {
    font-family: 'Roboto', Arial, sans-serif;
    background: url('img/bg.jpg') center center/cover no-repeat fixed, #fff;
    color: #222;
    margin: 0;
    padding: 0;
    min-height: 100vh;
    transition: background 0.6s;
}


header {
    font-family: 'Montserrat', Arial, sans-serif;
    letter-spacing: 1px;
}
h1, h2, h3 {
    font-family: 'Montserrat', 'Segoe UI', Arial, sans-serif;
    letter-spacing: 1px;
}
h1 {
    font-size: 2.7rem;
    margin-bottom: 0.5rem;
    font-family: 'Montserrat', Arial, sans-serif;
    color: #222;
    text-shadow: 0 2px 12px rgba(0,0,0,0.07);
}
h2 {
    font-size: 2rem;
    color: #2d3748;
    margin-bottom: 0.7rem;
}
/* Blur/Glass Effekt für Karten */
.card, .big-card, .mini-card, .video-card {
    background: rgba(255,255,255,0.55);
    border-radius: 22px;
    box-shadow: 0 6px 32px rgba(60,60,90,0.10), 0 1.5px 6px rgba(0,0,0,0.04);
    padding: 2.7rem 2.2rem;
    margin-bottom: 2.5rem;
    font-size: 1.13rem;
    transition: box-shadow 0.25s, transform 0.18s;
    border: 1.5px solid #e0e7ef;
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(12px) saturate(1.2);
    -webkit-backdrop-filter: blur(12px) saturate(1.2);
}
}
.card-large {
    max-width: 420px;
    min-width: 320px;
    font-size: 1.25rem;
}
.button-main {
    display: inline-block;
    background: #4a7c59;
    color: #fff;
    padding: 1.2rem 3rem;
    border-radius: 14px;
    text-decoration: none;
    font-size: 1.5rem;
    font-family: 'Montserrat', Arial, sans-serif;
    font-weight: 700;
    margin-top: 2.2rem;
    box-shadow: 0 2px 12px rgba(60,60,90,0.10);
    border: none;
    cursor: pointer;
    letter-spacing: 1px;
    text-align: center;
    min-width: 180px;
    transition: background 0.25s, transform 0.18s, box-shadow 0.18s;
}
.button-main:hover {
    background: #388e3c;
    color: #fff;
    transform: translateY(-2px) scale(1.04);
    box-shadow: 0 8px 32px rgba(60,60,90,0.16);
}
.price {
    font-size: 2rem;
    color: #222;
    font-weight: bold;
    margin: 1.5rem 0 1rem 0;
    letter-spacing: 1px;
    font-family: 'Montserrat', Arial, sans-serif;
}
nav a {
    color: #222;
    text-decoration: none;
    font-weight: 600;
    font-family: 'Montserrat', Arial, sans-serif;
    font-size: 1.1rem;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: background 0.18s, color 0.18s;
}
nav a:hover {
    background: #fff;
    color: #fff;
}
}
header {
    background: #fff;
    color: #111;
    padding: 0 0 1.5rem 0;
    text-align: center;
    box-shadow: 0 4px 16px rgba(0,0,0,0.08);
    animation: fadeInDown 1s;
}
nav a {
    color: #111;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    transition: background 0.2s, color 0.2s;
}
nav a:hover {
    background: #111;
    color: #fff;
}
@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-40px); }
    to { opacity: 1; transform: translateY(0); }
}
main {
    max-width: 900px;
    margin: 2.5rem auto;
    background: #fff;
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.07);
    animation: fadeIn 1.2s;
}
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}
.button-main {
    display: inline-block;
    background: #111;
    color: #fff;
    padding: 1.2rem 3rem;
    border-radius: 10px;
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: 600;
    margin-top: 2.2rem;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    border: none;
    cursor: pointer;
}
.card {
    background: #f5f5f5;
    border-radius: 16px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    padding: 2.5rem 2rem;
    margin-bottom: 2.5rem;
    font-size: 1.1rem;
}
.card-large {
    max-width: 400px;
    min-width: 320px;
    font-size: 1.25rem;
}
.twint-btn {
    background: #fff;
    color: #111;
    border: 2px solid #111;
    border-radius: 8px;
    padding: 1rem 2.5rem;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s, color 0.3s, border 0.3s, transform 0.2s, box-shadow 0.2s;
    margin-top: 0.5rem;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}
.twint-btn:hover {
    background: #111;
    color: #fff;
    border: 2px solid #111;
    transform: translateY(-4px) scale(1.07);
    box-shadow: 0 6px 24px rgba(0,0,0,0.13);
}
.price {
    font-size: 2rem;
    color: #111;
    font-weight: bold;
    margin: 1.5rem 0 1rem 0;
    letter-spacing: 1px;
}
input, select, button {
    font-size: 1rem;
    padding: 0.7rem;
    border-radius: 6px;
    border: 1px solid #111;
    margin-top: 0.5rem;
    width: 100%;
    box-sizing: border-box;
    margin-bottom: 1rem;
    transition: border 0.3s;
    background: #fff;
    color: #111;
}
input:focus, select:focus {
    border: 1.5px solid #111;
    outline: none;
}
.success {
    color: #111;
    font-weight: bold;
    margin-top: 1.5rem;
    text-align: center;
    font-size: 1.2rem;
    animation: fadeIn 1.2s;
}
.locked {
    color: #111;
    font-weight: bold;
    text-align: center;
    margin-bottom: 2rem;
    font-size: 1.1rem;
    animation: fadeIn 1.2s;
}
.video-list {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    justify-content: center;
    margin-top: 2rem;
}
.video-card {
    width: 320px;
    animation: fadeIn 1.2s;
    display: flex;
    flex-direction: column;
    align-items: center;
}
video {
    width: 100%;
    border-radius: 8px;
    margin-bottom: 0.5rem;
    background: #000;
}