/* --- Algemene stijl --- */
body {
    font-family: Calibri, Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: #eef2f7;
    color: #222;
}

/* --- Banner bovenaan --- */
.banner {
    background: url("../img/chemistry-banner.jpg") center/cover no-repeat;
    padding: 70px 20px;
    color: white;
    text-shadow: 0 0 12px black;
    border-bottom: 4px solid #002244;
}

/* --- Navigatie in blokken --- */
nav {
    margin-top: 20px;
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

nav a {
    background: rgba(255,255,255,0.15);
    padding: 12px 20px;
    border-radius: 8px;
    font-size: 20px;
    font-weight: bold;
    color: white;
    text-decoration: none;
    backdrop-filter: blur(4px);
    border: 1px solid rgba(255,255,255,0.25);
    transition: 0.2s;
}

nav a:hover {
    background: rgba(255,255,255,0.35);
    transform: translateY(-2px);
}

/* --- Dropdown container --- */
.dropdown {
    position: relative;
    display: inline-block;
}

/* --- Dropdown knop --- */
.dropbtn {
    background: rgba(255,255,255,0.20);
    color: white;
    padding: 14px 26px;
    font-size: 22px;
    font-weight: bold;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    backdrop-filter: blur(6px);
    border: 2px solid rgba(255,255,255,0.35);
    transition: 0.25s ease;
    box-shadow: 0 4px 12px rgba(0,0,0,0.25);
}

.dropbtn:hover {
    background: rgba(255,255,255,0.35);
    transform: translateY(-3px);
    box-shadow: 0 6px 16px rgba(0,0,0,0.35);
}

/* --- Dropdown inhoud --- */
.dropdown-content {
    display: none;
    position: absolute;
    background: rgba(0,0,0,0.85);
    min-width: 300px;
    border-radius: 12px;
    padding: 10px 0;
    box-shadow: 0 10px 25px rgba(0,0,0,0.4);
    z-index: 10;
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,255,255,0.15);
    animation: fadeIn 0.25s ease;
}

/* --- Links in dropdown --- */
.dropdown-content a {
    color: white;
    padding: 14px 20px;
    text-decoration: none;
    display: block;
    font-size: 18px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    transition: 0.2s ease;
}

.dropdown-content a:hover {
    background: rgba(255,255,255,0.15);
    padding-left: 28px;
}

/* --- Dropdown tonen bij hover --- */
.dropdown:hover .dropdown-content {
    display: block;
}

/* --- Fade-in animatie --- */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* --- Contentbox --- */
main {
    padding: 40px;
    background: white;
    margin: 50px auto;
    width: 90%;
    max-width: 1100px;
    border-radius: 14px;
    box-shadow: 0 0 20px rgba(0,0,0,0.12);
}

/* --- Titels --- */
h2 {
    font-size: 34px;
    margin-bottom: 10px;
}

h3 {
    margin-top: 50px;
    font-size: 28px;
}

/* --- Hoofdstuk-kaarten --- */
.card {
    position: relative;
    height: 260px;
    background-size: cover;
    background-position: center;
    border-radius: 14px;
    margin: 30px 0;
    overflow: hidden;
    box-shadow: 0 8px 20px rgba(0,0,0,0.25);
    cursor: pointer;
    transition: transform 0.25s, box-shadow 0.25s;
}

.card:hover {
    transform: scale(1.04);
    box-shadow: 0 12px 28px rgba(0,0,0,0.35);
}

/* --- Tekstvak op kaart --- */
.card .label {
    position: absolute;
    bottom: 0;
    width: 100%;
    background: rgba(0,0,0,0.55);
    padding: 18px;
    text-align: center;
    color: white;
    font-size: 24px;
    font-weight: bold;
    backdrop-filter: blur(6px);
    border-top: 1px solid rgba(255,255,255,0.2);
}

/* --- Klikbare kaarten --- */
a.card {
    display: block;
    text-decoration: none;
    color: inherit;
}

/* --- Footer --- */
footer {
    text-align: center;
    padding: 15px;
    background: #003366;
    color: white;
    margin-top: 40px;
}

/* --- Professionele download-knoppen (compact & strak) --- */
.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: #0055aa;
    color: white;
    padding: 12px 18px;
    border-radius: 8px;
    font-size: 18px;
    font-weight: bold;
    text-decoration: none;
    border: 2px solid #003f80;
    transition: 0.25s ease;
    box-shadow: 0 4px 10px rgba(0,0,0,0.15);
}

.download-btn:hover {
    background: #003f80;
    transform: translateY(-2px);
    box-shadow: 0 6px 14px rgba(0,0,0,0.25);
}

/* Icoon in de knop */
.download-btn img {
    width: 22px;
    height: 22px;
    filter: brightness(0) invert(1);
}