body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;

    background-color: #f4f5f7;
    color: #333;

    margin: 0;
    padding: 0;
}

/* ---------- Main content card ---------- */

.container {
    max-width: 980px;

    margin: 50px auto 80px auto;

    background: white;

    border-radius: 16px;

    box-shadow:
        0 4px 20px rgba(0,0,0,0.06);

    padding: 0;
}

/* ---------- Header ---------- */

.header {
    padding: 45px 70px 30px 70px;

    border-bottom: 1px solid #ececec;
}

h1 {
    margin: 0;

    font-size: 3em;
    font-weight: 500;

    color: #222;
}

.subtitle {
    margin-top: 18px;

    font-size: 1.15em;
    line-height: 1.7;

    color: #666;
}

.tagline {
    margin-top: 18px;
    font-size: 0.72em;
    font-weight: 400;
    letter-spacing: 0.08em;
    color: #666;
}
/* ---------- Navigation ---------- */

.navbar {
    display: flex;
    gap: 28px;

    padding: 18px 70px;

    background: #fafafa;

    border-bottom: 1px solid #ececec;

    font-size: 0.98em;

    letter-spacing: 0.02em;
}

.navbar a {
    color: #444;

    text-decoration: none;

    padding-bottom: 4px;

    transition: all 0.15s ease;
}

.navbar a:hover {
    color: #000;

    border-bottom: 2px solid #4c78c2;
}

/* ---------- Content ---------- */

.content {
    padding: 50px 70px 60px 70px;
}

h2 {
    margin-top: 2.6em;
    margin-bottom: 1em;

    font-size: 1.5em;
    font-weight: 500;

    color: #333;
}

p {
    line-height: 1.9;

    margin-bottom: 1.4em;

    color: #444;
}

/* ---------- Lists ---------- */

.software-list {
    padding-left: 1.4em;
}

.software-list li {
    margin-bottom: 1em;

    line-height: 1.8;
}

/* ---------- Links ---------- */

a {
    color: #3366aa;
}

a:hover {
    color: #1d4f91;
}

/* ---------- Footer ---------- */

.footer {
    margin-top: 70px;

    padding-top: 24px;

    border-top: 1px solid #ececec;

    color: #888;

    font-size: 0.92em;
}

/* ---------- Mobile ---------- */

@media (max-width: 900px) {

    .header,
    .navbar,
    .content {
        padding-left: 30px;
        padding-right: 30px;
    }

    .navbar {
        flex-wrap: wrap;
        gap: 16px;
    }

    h1 {
        font-size: 2.2em;
    }
}

/* ---------- Cards ---------- */

.software-card,
.collaboration-card,
.topic-card,
.contact-card {
    margin-top: 2em;
    margin-bottom: 2em;
    padding: 28px 34px;
    background: #fafafa;
    border: 1px solid #ececec;
    border-radius: 12px;
    transition: all 0.15s ease;
}

.software-card:hover,
.collaboration-card:hover,
.topic-card:hover,
.contact-card:hover {
    box-shadow: 0 4px 16px rgba(0,0,0,0.06);
    transform: translateY(-2px);
}

.software-card h3,
.collaboration-card h3,
.topic-card h3,
.contact-card h3 {
    margin-top: 0;
    margin-bottom: 0.8em;
    font-size: 1.35em;
    font-weight: 500;
    color: #222;
}

.lead {
    font-size: 1.08em;
    color: #555;
}

.callout {
    margin-top: 2em;
    padding: 20px 24px;
    background: #f7f9fc;
    border-left: 4px solid #4c78c2;
    border-radius: 8px;
    line-height: 1.7;
    color: #444;
}

.software-image {

    width: 100%;

    max-width: 560px;

    display: block;

    margin-left: auto;
    margin-right: auto;

    margin-top: 1.5em;
    margin-bottom: 1.8em;

    border-radius: 10px;

    border: 1px solid #e5e5e5;

    box-shadow:
        0 2px 10px rgba(0,0,0,0.05);
}

.mobile-gallery {

    display: flex;

    gap: 24px;

    margin-top: 1.5em;
    margin-bottom: 2em;

    flex-wrap: wrap;
}

.mobile-image {

    width: 260px;

    border-radius: 18px;

    border: 1px solid #dddddd;

    box-shadow:
        0 2px 10px rgba(0,0,0,0.06);
}