* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 16px;
    font-family: Arial, sans-serif;
    background: #f4f6f8;
    color: #111827;
    font-size: 16px;
}

nav {
    position: sticky;
    top: 12px;

    margin-bottom: 18px;

    background: #111827;
    padding: 12px;

    border-radius: 18px;

    display: flex;
    gap: 8px;
    overflow-x: auto;
    z-index: 10;
}

nav a {
    color: white;
    text-decoration: none;
    background: #1f2937;
    padding: 10px 14px;
    border-radius: 999px;
    font-size: 14px;
    white-space: nowrap;
    font-weight: 600;
}

nav a:hover {
    background: #2563eb;
}

main {
    width: 100%;
    max-width: 520px;
    margin: 0 auto;
    padding: 20px 0 40px;
}

.card {
    background: white;
    padding: 22px 18px;
    border-radius: 18px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.08);
}

h1 {
    font-size: 24px;
    margin: 0 0 20px;
}

label {
    display: block;
    margin-bottom: 7px;
    font-weight: 700;
    font-size: 15px;
}

input,
select,
textarea {
    width: 100%;
    min-height: 46px;
    padding: 12px 14px;
    border: 1px solid #d1d5db;
    border-radius: 12px;
    font-size: 16px;
    margin-bottom: 16px;
    background: white;
}

textarea {
    min-height: 110px;
    resize: vertical;
}

button {
    width: 100%;
    min-height: 50px;
    background: #2563eb;
    color: white;
    border: none;
    border-radius: 14px;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
}

button:hover {
    background: #1d4ed8;
}

p {
    background: #dcfce7;
    color: #166534;
    padding: 12px;
    border-radius: 12px;
    font-weight: 600;
}

.error {
    background: #fee2e2;
    color: #991b1b;
}

@media (min-width: 700px) {
    main {
        padding-top: 40px;
    }

    .card {
        padding: 32px;
    }
}