diff --git a/src/lib/CalendarMonth.svelte b/src/lib/CalendarMonth.svelte
new file mode 100644
index 0000000..d90b195
--- /dev/null
+++ b/src/lib/CalendarMonth.svelte
@@ -0,0 +1,101 @@
+<script>
+    import Tooltip from './Tooltip.svelte';
+
+    export let year;
+    export let month;
+    export let holidays = [];
+    export let optimizedDaysOff = [];
+
+    function getDaysInMonth(year, month) {
+        return new Date(year, month + 1, 0).getDate();
+    }
+
+    function getFirstDayOfMonth(year, month) {
+        return new Date(year, month, 1).getDay();
+    }
+
+    let daysInMonth = getDaysInMonth(year, month);
+    let firstDay = getFirstDayOfMonth(year, month);
+
+    function getHoliday(day) {
+        return holidays.find(holiday => 
+            holiday.date.getFullYear() === year &&
+            holiday.date.getMonth() === month &&
+            holiday.date.getDate() === day
+        );
+    }
+
+    function isOptimizedDayOff(day) {
+        return optimizedDaysOff.some(date => 
+            date.getFullYear() === year &&
+            date.getMonth() === month &&
+            date.getDate() === day
+        );
+    }
+</script>
+
+<style>
+    .calendar {
+        display: grid;
+        grid-template-columns: repeat(7, 1fr);
+        gap: 1px;
+        border: 1px solid #444;
+        padding: 5px;
+        margin: 5px;
+        box-sizing: border-box;
+        width: 100%;
+        height: auto;
+    }
+    .day {
+        aspect-ratio: 1;
+        text-align: center;
+        font-size: 0.7em;
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        color: #ddd;
+        background-color: #222;
+        position: relative;
+    }
+    
+    .day:hover {
+        :global(.tooltip) {
+            opacity: 1;
+            pointer-events: auto;
+        }
+    }
+    .weekend {
+        background-color: #333;
+    }
+    .holiday {
+        background-color: #555;
+        cursor: pointer;
+    }
+    .optimized {
+        background-color: #4caf50;
+        color: white;
+    }
+    .month-name {
+        grid-column: span 7;
+        text-align: center;
+        font-weight: bold;
+        font-size: 0.8em;
+        margin-bottom: 2px;
+        color: #fff;
+    }
+</style>
+
+<div class="calendar">
+    <div class="month-name">{new Date(year, month).toLocaleString('default', { month: 'long' })}</div>
+    {#each Array.from({ length: firstDay }) as _}
+        <div class="day"></div>
+    {/each}
+    {#each Array.from({ length: daysInMonth }, (_, i) => i + 1) as day}
+        <div class="day {(firstDay + day - 1) % 7 === 0 || (firstDay + day - 1) % 7 === 6 ? 'weekend' : ''} {getHoliday(day) ? 'holiday' : ''} {isOptimizedDayOff(day) ? 'optimized' : ''}">
+            {day}
+            {#if getHoliday(day)}
+                <Tooltip text={getHoliday(day).name} />
+            {/if}
+        </div>
+    {/each}
+</div> 
\ No newline at end of file
diff --git a/src/lib/Tooltip.svelte b/src/lib/Tooltip.svelte
new file mode 100644
index 0000000..7f1b820
--- /dev/null
+++ b/src/lib/Tooltip.svelte
@@ -0,0 +1,40 @@
+<script>
+    export let text = '';
+</script>
+
+<style>
+    .tooltip {
+        position: absolute;
+        background-color: #333;
+        color: #fff;
+        padding: 5px;
+        border-radius: 3px;
+        font-size: 0.8em;
+        white-space: nowrap;
+        z-index: 1000;
+        pointer-events: none;
+        opacity: 0;
+        transition: opacity 0.2s;
+    }
+
+    .tooltip::after {
+        content: '';
+        position: absolute;
+        top: 100%; /* Position the tail at the bottom of the tooltip */
+        left: 50%;
+        transform: translateX(-50%);
+        border-width: 5px;
+        border-style: solid;
+        border-color: #333 transparent transparent transparent;
+    }
+
+    .tooltip {
+        bottom: 100%;
+        left: 50%;
+        transform: translateX(-50%);
+    }
+</style>
+
+<div class="tooltip">
+    {text}
+</div> 
\ No newline at end of file