body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: #f4f7f9;
    color: #333;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

.container {
    background-color: #fff;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 600px;
    text-align: center;
}

h1 {
    color: #1a73e8;
    margin-bottom: 0.5rem;
}

p {
    color: #666;
    margin-bottom: 1.5rem;
}

textarea {
    width: 100%;
    height: 200px;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-family: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", monospace;
    font-size: 0.9rem;
    resize: vertical;
    margin-bottom: 1rem;
    box-sizing: border-box;
}

button {
    background-color: #1a73e8;
    color: #fff;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #155ab6;
}

#results {
    margin-top: 1.5rem;
    text-align: left;
}

.result-item {
    padding: 0.75rem;
    border-bottom: 1px solid #eee;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.result-item:last-child {
    border-bottom: none;
}

.key-prefix {
    font-family: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", monospace;
    font-size: 0.9rem;
}

.status {
    font-weight: bold;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.8rem;
}

.status.valid {
    background-color: #e6f4ea;
    color: #34a853;
}

.status.invalid {
    background-color: #fce8e6;
    color: #ea4335;
}

.status.checking {
    background-color: #e8f0fe;
    color: #1a73e8;
}