* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #080808;
    color: #ffffff;
    line-height: 1.6;
}


/* NAVBAR */

.navbar {
    width: 100%;
    height: 75px;

    display: flex;
    align-items: center;
    justify-content: space-between;

    padding: 0 8%;

    border-bottom: 1px solid #222;

    position: sticky;
    top: 0;

    background: rgba(8, 8, 8, 0.9);

    backdrop-filter: blur(12px);

    z-index: 100;
}

.logo {
    font-size: 22px;
    font-weight: bold;
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links a {
    color: #aaa;
    text-decoration: none;
    transition: 0.2s;
}

.nav-links a:hover {
    color: white;
}


/* HERO */

.hero {
    min-height: 650px;

    display: flex;
    align-items: center;
    justify-content: center;

    text-align: center;

    padding: 80px 20px;

    background:
        radial-gradient(
            circle at top,
            #202020 0%,
            #080808 55%
        );
}

.hero-content {
    max-width: 850px;
}

.badge {
    display: inline-block;

    padding: 7px 15px;

    border: 1px solid #333;

    border-radius: 50px;

    color: #aaa;

    font-size: 14px;

    margin-bottom: 25px;
}

.hero h1 {
    font-size: clamp(42px, 7vw, 78px);

    line-height: 1.05;

    letter-spacing: -3px;

    margin-bottom: 25px;
}

.hero h1 span {
    color: #888;
}

.hero p {
    max-width: 650px;

    margin: auto;

    color: #999;

    font-size: 18px;

    margin-bottom: 35px;
}

.hero-button {
    display: inline-block;

    padding: 14px 25px;

    background: white;

    color: black;

    text-decoration: none;

    border-radius: 8px;

    font-weight: bold;

    transition: 0.2s;
}

.hero-button:hover {
    transform: translateY(-2px);

    background: #ddd;
}


/* GENERAL SECTION */

.section {
    max-width: 1200px;

    margin: auto;

    padding: 100px 25px;
}

.section-heading {
    margin-bottom: 45px;
}

.section-heading > span {
    color: #777;

    font-size: 13px;

    letter-spacing: 2px;

    font-weight: bold;
}

.section-heading h2 {
    font-size: 42px;

    margin-top: 8px;

    letter-spacing: -1px;
}

.section-heading p {
    color: #888;

    margin-top: 8px;
}


/* SUBJECTS */

.subjects-grid {
    display: grid;

    grid-template-columns:
        repeat(4, 1fr);

    gap: 18px;
}

.subject-card {
    padding: 30px;

    background: #111;

    border: 1px solid #242424;

    border-radius: 15px;

    cursor: pointer;

    transition: 0.25s;
}

.subject-card:hover {
    transform: translateY(-5px);

    border-color: #555;
}

.subject-icon {
    font-size: 35px;

    margin-bottom: 20px;
}

.subject-card h3 {
    font-size: 20px;

    margin-bottom: 8px;
}

.subject-card p {
    color: #888;

    font-size: 14px;

    min-height: 65px;
}

.subject-card span {
    display: block;

    margin-top: 20px;

    color: #ccc;

    font-size: 14px;
}


/* SEARCH */

.search-container {
    margin-bottom: 20px;
}

#searchInput {
    width: 100%;

    padding: 17px 20px;

    background: #111;

    color: white;

    border: 1px solid #292929;

    border-radius: 10px;

    outline: none;

    font-size: 16px;
}

#searchInput:focus {
    border-color: #555;
}


/* FILTERS */

.filters {
    display: flex;

    gap: 10px;

    flex-wrap: wrap;

    margin-bottom: 30px;
}

.filter {
    background: #111;

    color: #999;

    border: 1px solid #292929;

    padding: 9px 16px;

    border-radius: 50px;

    cursor: pointer;
}

.filter:hover,
.filter.active {
    background: white;

    color: black;
}


/* MATERIALS */

.materials-grid {
    display: grid;

    gap: 15px;
}

.material-card {
    display: flex;

    align-items: center;

    gap: 20px;

    padding: 20px;

    background: #111;

    border: 1px solid #242424;

    border-radius: 13px;

    transition: 0.2s;
}

.material-card:hover {
    border-color: #444;
}

.file-icon {
    min-width: 55px;

    height: 65px;

    display: flex;

    align-items: center;

    justify-content: center;

    background: #1d1d1d;

    border-radius: 9px;

    font-size: 12px;

    font-weight: bold;

    color: #aaa;
}

.material-info {
    flex: 1;
}

.material-subject {
    color: #777;

    font-size: 12px;

    text-transform: uppercase;

    letter-spacing: 1px;
}

.material-info h3 {
    margin-top: 4px;

    font-size: 18px;
}

.material-info p {
    color: #888;

    font-size: 14px;
}

.material-info small {
    color: #666;

    display: block;

    margin-top: 4px;
}

.download-button {
    padding: 10px 16px;

    border: 1px solid #333;

    border-radius: 8px;

    text-decoration: none;

    color: white;

    font-size: 14px;

    white-space: nowrap;
}

.download-button:hover {
    background: white;

    color: black;
}


/* INFO */

.info-section {
    max-width: 1200px;

    margin: 0 auto;

    padding: 80px 25px;

    border-top: 1px solid #222;

    border-bottom: 1px solid #222;
}

.info-section > div {
    max-width: 650px;
}

.info-section span {
    color: #777;

    font-size: 13px;

    letter-spacing: 2px;
}

.info-section h2 {
    font-size: 38px;

    line-height: 1.2;

    margin: 10px 0;
}

.info-section p {
    color: #888;
}


/* FOOTER */

footer {
    text-align: center;

    padding: 60px 20px;

    color: #777;
}

.footer-logo {
    color: white;

    font-size: 20px;

    font-weight: bold;

    margin-bottom: 8px;
}

.copyright {
    margin-top: 25px;

    font-size: 13px;

    color: #555;
}


/* MOBILE */

@media (max-width: 900px) {

    .subjects-grid {
        grid-template-columns:
            repeat(2, 1fr);
    }

}


@media (max-width: 600px) {

    .navbar {
        padding: 0 20px;
    }

    .nav-links {
        display: none;
    }

    .hero {
        min-height: 600px;
    }

    .hero h1 {
        letter-spacing: -2px;
    }

    .section {
        padding: 70px 18px;
    }

    .section-heading h2 {
        font-size: 32px;
    }

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

    .material-card {
        align-items: flex-start;

        flex-wrap: wrap;
    }

    .material-info {
        min-width: calc(100% - 75px);
    }

    .download-button {
        width: 100%;

        text-align: center;
    }

}