* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', sans-serif;
    margin: 0;
    padding: 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    color: #333;
    line-height: 1.6;
}

nav {
    width: 100%;
    max-width: 600px;
    margin-bottom: 20px;
}

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 20px;
    padding: 10px;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

nav a {
    text-decoration: none;
    color: #667eea;
    font-weight: 500;
    transition: color 0.3s;
}

nav a:hover {
    color: #764ba2;
}

main {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 16px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    padding: 30px;
    max-width: 600px;
    width: 100%;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

h1 {
    text-align: center;
    margin-bottom: 20px;
    color: #2d3748;
    font-size: 2.5em;
}

form {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

label {
    font-weight: 600;
    color: #4a5568;
}

input, textarea {
    padding: 10px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-family: inherit;
    font-size: 1em;
    transition: border-color 0.3s;
}

input:focus, textarea:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

textarea {
    resize: vertical;
    min-height: 100px;
}

button {
    padding: 12px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.3s, box-shadow 0.3s;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

button:focus {
    outline: 2px solid #4c51bf;
    outline-offset: 2px;
}

.error-message {
    color: #e53e3e;
    font-size: 0.9em;
    margin-top: 5px;
    display: none;
}

.success-message {
    color: #38a169;
    font-size: 1em;
    margin-top: 15px;
    display: none;
    text-align: center;
    font-weight: 600;
}

@media (min-width: 480px) {
    main {
        padding: 40px;
    }

    h1 {
        font-size: 3em;
    }
}

@media (min-width: 768px) {
    main {
        padding: 50px;
    }
}