* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --background-color: #ffffff;
    --text-color: #1f2937;
    --border-color: #e5e7eb;
    --hover-color: #f3f4f6;
    --border-radius: 8px;
    --transition: all 0.2s ease;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: #f9fafb;
    padding: 20px;
    gap: 1rem;
}

.calendar-container {
    background: var(--background-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 1.5rem;
    width: 95%;
    max-width: 400px;
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.calendar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    gap: 0.5rem;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.date-selectors {
    display: flex;
    gap: 0.5rem;
}

.date-select {
    padding: 0.375rem 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    color: var(--text-color);
    background: var(--background-color);
    cursor: pointer;
    transition: var(--transition);
    outline: none;
    font-weight: 500;
}

.date-select:hover, .date-select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.1);
}

.nav-btn {
    background: var(--background-color);
    border: 1px solid var(--border-color);
    font-size: 0.875rem;
    cursor: pointer;
    color: var(--text-color);
    padding: 0.375rem;
    border-radius: var(--border-radius);
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2rem;
    height: 2rem;
}

.nav-btn:hover {
    background: var(--hover-color);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.today-btn {
    padding: 0.375rem 0.75rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    font-size: 0.875rem;
    transition: var(--transition);
}

.today-btn:hover {
    background: var(--secondary-color);
}

.calendar-weekdays {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 0.25rem;
    margin-bottom: 0.5rem;
    text-align: center;
    font-weight: 500;
    color: #6b7280;
    font-size: 0.75rem;
    text-transform: uppercase;
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 0.25rem;
    padding: 0.25rem;
}

.calendar-day {
    aspect-ratio: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 0.875rem;
    cursor: pointer;
    border-radius: var(--border-radius);
    transition: var(--transition);
    position: relative;
    font-weight: 500;
    color: var(--text-color);
    height: 2rem;
}

.calendar-day:hover {
    background: var(--hover-color);
}

.calendar-day.today {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
}

.calendar-day.other-month {
    color: #9ca3af;
}

.calendar-day.selected {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
}

.selected-date-info {
    margin-top: 1rem;
    padding: 0.75rem;
    background: var(--hover-color);
    border-radius: var(--border-radius);
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-color);
    min-height: 2.5rem;
    border: 1px solid var(--border-color);
}

.calendar-footer {
    text-align: center;
    color: #6b7280;
    font-size: 0.875rem;
    margin-top: 0.5rem;
    font-weight: 500;
}

@media (max-width: 400px) {
    .calendar-container {
        padding: 1rem;
    }
    
    .calendar-day {
        font-size: 0.75rem;
        height: 1.75rem;
    }
    
    .date-select {
        font-size: 0.75rem;
        padding: 0.25rem 0.5rem;
    }
    
    .header-left {
        flex-wrap: wrap;
    }
    
    .date-selectors {
        order: 2;
        width: 100%;
        margin-top: 0.5rem;
    }
    
    .date-select {
        flex: 1;
    }
    
    .today-btn {
        font-size: 0.75rem;
        padding: 0.25rem 0.5rem;
    }
}