body {
    margin: 0;
    background-color: #0d1117;
    color: #c9d1d9;
    font-family: 'Segoe UI', Tahoma, sans-serif;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    text-align: center;
    padding: 20px 0;
    background: #161b22;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.5);
}

header h1 {
    margin: 0;
    color: #58a6ff;
    font-size: 2rem;
}

header h2 {
    margin: 5px 0 0;
    font-weight: normal;
    color: #8b949e;
}

main {
    flex: 1;
    max-width: 800px;
    margin: auto;
    padding: 20px;
    text-align: center;
}

.input-container {
    margin: 20px 0;
}

input[type="datetime-local"] {
    padding: 10px;
    font-size: 1rem;
    border: 1px solid #30363d;
    border-radius: 6px;
    background: #161b22;
    color: #c9d1d9;
    outline: none;
}

button {
    padding: 10px 20px;
    font-size: 1rem;
    margin-left: 10px;
    border: none;
    border-radius: 6px;
    background: #238636;
    color: white;
    cursor: pointer;
    transition: background 0.3s;
}

button:hover {
    background: #2ea043;
}

.output-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #161b22;
    padding: 10px 15px;
    border: 1px solid #30363d;
    border-radius: 6px;
    margin: 10px 0;
}

.code-block {
    font-family: monospace;
    background: #0d1117;
    padding: 6px 10px;
    border-radius: 5px;
    border: 1px solid #30363d;
    color: #58a6ff;
}

.copy-btn {
    background: none;
    border: none;
    color: #58a6ff;
    cursor: pointer;
    font-size: 1.5rem;
}

footer {
    text-align: center;
    padding: 10px 0;
    font-size: 0.85rem;
    color: #6e7681;
    background: #161b22;
    border-top: 1px solid #21262d;
}