:root {
    --bg: #f6f8fb;
    --surface: #ffffff;
    --text: #17263b;
    --muted: #64748b;
    --accent: #347daf;
    --border: #e1e7ee;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: system-ui, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

.container {
    width: min(1100px, 92%);
    margin: 0 auto;
}

.site-header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    padding: 20px 0;
}

.logo {
    font-weight: 800;
    text-decoration: none;
    color: var(--text);
    letter-spacing: 1px;
}

.nav-links {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.nav-links a {
    color: var(--muted);
    text-decoration: none;
}

main {
    padding: 48px 0;
    min-height: 75vh;
}

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 28px;
    margin-bottom: 24px;
}

button {
    background: var(--accent);
    color: white;
    border: 0;
    border-radius: 8px;
    padding: 12px 20px;
    font: inherit;
    cursor: pointer;
}

input, select {
    display: block;
    width: 100%;
    max-width: 440px;
    padding: 10px;
    margin: 8px 0 20px;
    border: 1px solid var(--border);
    border-radius: 7px;
}

.mesh-viewer {
    height: 440px;
    border-radius: 12px;
    overflow: hidden;
    background: #edf2f7;
}

progress {
    width: 100%;
    height: 18px;
}

.site-footer {
    padding: 30px 0;
    border-top: 1px solid var(--border);
    color: var(--muted);
}

@media (max-width: 700px) {
    .nav {
        flex-direction: column;
        align-items: flex-start;
    }

    .mesh-viewer {
        height: 320px;
    }
}