:root {
    --bg-color: #f0f0f0;
    --fg-color: #333;
    --accent-color: #666;
}

body {
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
    background-color: var(--bg-color);
    color: var(--fg-color);
    transition: background-color 0.5s ease, color 0.5s ease;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

#app {
    width: 100%;
    max-width: 800px;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    height: 100%;
    box-sizing: border-box;
}

header {
    display: flex;
    justify-content: flex-end;
    padding-bottom: 2rem;
}

select {
    padding: 0.5rem;
    border-radius: 4px;
    border: 1px solid var(--accent-color);
    background: transparent;
    color: var(--fg-color);
    font-size: 1rem;
    cursor: pointer;
}

main {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
}

#message {
    font-size: 2.5rem;
    font-weight: 700;
    line-height: 1.4;
    margin: 0;
}

footer {
    padding-top: 2rem;
    text-align: center;
    opacity: 0.7;
    font-size: 0.9rem;
}

#date-display {
    margin-bottom: 1rem;
}

.nav-controls {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

button {
    padding: 0.5rem 1rem;
    border-radius: 4px;
    border: 1px solid var(--accent-color);
    background: transparent;
    color: var(--fg-color);
    cursor: pointer;
    font-size: 1rem;
    transition: opacity 0.2s;
}

button:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

button:hover:not(:disabled) {
    background-color: rgba(255,255,255,0.1);
}

@media (max-width: 600px) {
    #message {
        font-size: 1.8rem;
    }
}