body, html {
    /* Allow content to extend beyond viewport height and scroll on mobile */
    min-height: 100vh;
    margin: 0;
    padding: 0;
    overflow-x: hidden; /* prevent horizontal scroll */
    overflow-y: auto;   /* allow vertical scroll */
    user-select: none;
}

body {
    font-family: sans-serif;
    display: flex;
    flex-direction: column;
    justify-content: start;
    align-items: center;
    background: linear-gradient(to right, #00a9e4, #002352);
    color: white;
}

.header {
    --br-radius: 50%;
    width: 120%;
    background: white;
    padding: 5rem 0;
    border-bottom-left-radius: var(--br-radius);
    border-bottom-right-radius: var(--br-radius);
    text-align: center;
}

.button-container {
    width: 100%;
    align-self: center;
    display: flex;
    padding: 2rem;
    position: absolute;
    bottom: 0;
}

.next {
    text-decoration: none;
    background: transparent;
    border: none;
    color: white;
    font-weight: bold;
    font-size: 3rem;
    cursor: pointer;
    padding: 1rem 3rem;
    margin: 0 2rem;
}

.next:hover {
    font-size: 3.5rem;
}

.main {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: start;
    flex-grow: 1;
    width: 100%;
    padding: 3rem;
    text-align: center;
}

.main h1 {
    font-size: 3.5rem;
    margin: 0;
}

.img-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
}


.logo {
    max-width: min(80vw, 420px);
    height: auto;
    display: inline-block;
}

img {
    max-width: 100%;
    height: auto;
}

#quiz-container {
    flex-grow: 1;
    text-align: center;
    margin-top: 2rem;
    padding: 0 2rem;
}

#question {
    font-size: 3.5em;
    margin-bottom: 20px;
}

.btn-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 10px;
    margin: 20px 0;
}

.btn {
    background-color: #007bff;
    border: 1px solid #007bff;
    border-radius: 5px;
    padding: 10px;
    color: white;
    font-size: 3rem;
    cursor: pointer;
    margin: 1rem;
}

.btn:hover {
    background-color: #0056b3;
}

.btn.correct {
    background-color: #28a745;
}

.btn.wrong {
    background-color: #dc3545;
}


#next-btn {
    margin-top: 20px;
    padding: 10px 20px;
}

.hide {
    display: none;
}

#final {
    font-size: 200%;
}

#final h1, #final h2 {
    margin-top: 0;
}

@media (max-width: 600px) {
    .main {
        padding: 1rem;
        text-align: center;
    }
    .main h1 {
        font-size: clamp(1.25rem, 5.5vw + 0.5rem, 2rem);
        line-height: 1.2;
    }
    .header {
        padding: clamp(1.25rem, 6vw, 2rem) 0;
    }
    #question {
        font-size: clamp(1.25rem, 5vw + 0.5rem, 2rem);
        margin-bottom: 12px;
        line-height: 1.3;
        word-break: break-word;
    }
    .btn-grid {
        gap: 0.75rem;
        margin: 1rem 0 2rem;
        grid-template-columns: 1fr;
    }
    .btn {
        font-size: clamp(1rem, 4.5vw, 1.25rem);
        padding: 0.9rem 1rem;
        margin: 0;
        width: 100%;
        box-sizing: border-box;
    }
    .next {
        font-size: 1.25rem;
        padding: 0.75rem 1rem;
        margin: 0 0.5rem;
    }
    .next:hover {
        font-size: 1.25rem; /* avoid layout shift on mobile */
    }

    #quiz-container {
        padding: 0 1rem 5rem; /* space for sticky buttons */
    }

    #final {
        font-size: 120%;
    }
}