Added PageContainer handling responsive breakpoints.

frontend/src/components/page/PageContainer.vue

@@ -0,0 +1,28 @@
+<script setup lang="ts">
+</script>
+
+<template>
+    <div class="page-container">
+        <div class="content">
+            <slot></slot>
+        </div>
+    </div>
+</template>
+
+<style lang="scss" scoped>
+@import "../../scss/variables";
+@import "../../scss/mixins";
+
+.page-container {
+    display: flex;
+    justify-content: center;
+}
+
+@each $breakpoint, $width in $page-container-widths {
+    @include page-breakpoint($breakpoint) {
+        .content {
+            width: $width;
+        }
+    }
+}
+</style>