:root {
    /* button background */
    --bg: #f6f8fb;
    --border: #d7e0ee;
    /* outer square size */
    --btn-size: 72px;
    /* size of the circular + */
    --circle-size: 40px;
    /* accent color */
    --primary: #4fc3f7;
}

/* small responsive tweak */
@media (max-width:420px) {
    :root {
        --btn-size: 60px;
        --circle-size: 34px;
    }
}

* {
    margin: 0;
}

body {
    margin: 0;
}

.site-header {
    align-items: center;
    backdrop-filter: blur(10px);
    color: #000;
    display: flex;
    justify-content: center;
    padding: 1rem 2rem;
    position: sticky;
    /* stays above page content */
    z-index: 1000;
}

.site-header h1 {
    
    margin: 0;
    /* center the site title */
    text-align: center;
}

nav {
    align-items: center;
    backdrop-filter: blur(10px);
    color: #000;
    display: flex;
    justify-content: center;
    padding: 0;
    position: sticky;
    top: 0;
    /* stays above page content */
    z-index: 1000;

    display: flex;
    /* space between links */
    gap: 1.5rem;

}

.nav-link {
    color: #000;
    font-weight: 500;
    transition: color 0.3s ease;
    text-decoration: none;
}

.nav-link:hover {
    /* light blue hover color */
    color: #4fc3f7;
}

main {
    display: flex;
    /* left-to-right */
    flex-direction: row;
    /* optional: full height layout */
    min-height: 100vh;
    padding-top: 1rem;
}

.left-dock {
    background: #f9f9f9;
    border-right: 1px solid #e0e0e0;
    border-top: 1px solid #e0e0e0;
    overflow-y: auto;
    padding: 1rem;
    /* start below the navigation */
    width: 25%;
}

.content-area {
    flex: 1;
    padding: 1rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.button {
    padding: 0.5rem 1rem;
    font-size: 1rem;
    background-color: var(--primary);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}