:root {
    --primary-color: #007bff;
    --light-gray: #f4f4f4;
    --medium-gray: #ddd;
    --dark-gray: #333;
    --error-color: #dc3545;
    --bg-color: #ffffff;
    --text-color: #333;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    background-color: var(--light-gray);
    color: var(--text-color);
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

main {
    max-width: 600px;
    width: 100%;
    margin: 0 auto;
    padding: 25px;
    background-color: #fff;
    border: 1px solid var(--medium-gray);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

h1 {
    color: var(--dark-gray);
    text-align: center;
    margin-top: 0;
}

p {
    text-align: center;
    font-size: 1.1em;
    margin-bottom: 20px;
}

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

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    margin-bottom: 5px;
    font-weight: bold;
    color: #555;
}

.form-group small {
    margin-top: 5px;
    font-size: 0.85em;
    color: #777;
    text-align: center;
}

#vinInput, #apiKey {
    padding: 12px;
    font-size: 1rem;
    border: 1px solid var(--medium-gray);
    border-radius: 5px;
}

#vinInput {
    text-transform: uppercase;
}

#decodeButton {
    padding: 12px 20px;
    font-size: 1rem;
    font-weight: bold;
    color: #fff;
    background-color: var(--primary-color);
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    margin-top: 10px;
}

#decodeButton:hover {
    background-color: #0056b3;
}

#decodeButton:disabled {
    background-color: var(--medium-gray);
    cursor: not-allowed;
}

.hidden {
    display: none;
}

#results {
    margin-top: 25px;
    border-top: 1px dashed var(--medium-gray);
    padding-top: 20px;
}

#results-list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 12px;
}

.result-item {
    padding: 10px;
    background-color: var(--light-gray);
    border-radius: 5px;
    display: flex;
    justify-content: space-between;
}

.result-item strong {
    color: var(--dark-gray);
    padding-right: 10px;
    text-transform: capitalize;
}

#error {
    margin-top: 20px;
    padding: 12px;
    background-color: #f8d7da;
    color: var(--error-color);
    border: 1px solid #f5c6cb;
    border-radius: 5px;
    text-align: center;
}

#loading {
    display: flex;
    justify-content: center;
    margin-top: 25px;
}

.spinner {
    border: 4px solid var(--light-gray);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

footer {
    text-align: center;
    margin-top: 20px;
    font-size: 0.9em;
    color: #777;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

@media (min-width: 600px) {
    #results-list {
        grid-template-columns: 1fr 1fr;
    }
}