.game-site-header {
    position: sticky;
    top: 0;
    z-index: 100;

    width: 100vw;
    margin-top: 0;
    margin-right: calc(50% - 50vw);
    margin-bottom: 28px;
    margin-left: calc(50% - 50vw);
    padding: 12px clamp(18px, 5vw, 70px);

    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 24px;

    box-sizing: border-box;
    font-family:
        Arial,
        Helvetica,
        sans-serif;

    background: rgba(255, 255, 255, 0.96);
    border-bottom: 1px solid #dbeafe;
    box-shadow: 0 3px 14px rgba(30, 64, 175, 0.08);
}

.game-site-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
}

.game-site-logo img {
    width: 52px;
    height: 52px;
    object-fit: contain;
}

.game-site-logo-name {
    color: #15803d;
    font-size: clamp(18px, 2vw, 26px);
    font-weight: 800;
    white-space: nowrap;
}

.game-site-nav {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
}

.game-site-nav a {
    display: block;
    padding: 10px 14px;

    color: #1e3a8a;
    font-size: 15px;
    font-weight: 700;
    text-decoration: none;

    border-radius: 10px;

    transition:
        background-color 0.2s,
        color 0.2s,
        transform 0.2s;
}

.game-site-nav a:hover {
    color: white;
    background: #2563eb;
    transform: translateY(-2px);
}

.game-site-nav .game-account-link {
    color: white;
    background: #16a34a;
}

.game-site-nav .game-account-link:hover {
    background: #15803d;
}

.game-site-logo:focus-visible,
.game-site-nav a:focus-visible {
    outline: 4px solid #f93e3e;
    outline-offset: 3px;
}

.game-site-header[hidden],
body.play-mode .game-site-header,
body.student-mode .game-site-header,
body.active-game-mode .game-site-header {
    display: none;
}

@media (max-width: 900px) {
    .game-site-header {
        flex-direction: column;
        justify-content: center;
        gap: 10px;
        padding: 12px 18px;
    }

    .game-site-nav {
        justify-content: center;
        width: 100%;
    }
}

@media (max-width: 520px) {
    .game-site-logo {
        width: 100%;
        justify-content: center;
        gap: 6px;
    }

    .game-site-logo img {
        width: 34px;
        height: 34px;
    }

    .game-site-logo-name {
        font-size: 16px;
        white-space: normal;
        text-align: center;
    }

    .game-site-nav {
        gap: 5px;
    }

    .game-site-nav a {
        padding: 8px 9px;
        font-size: 13px;
    }
}