diff --git a/truthseeker/static/css/game_ui_lobby.css b/truthseeker/static/css/game_ui_lobby.css
new file mode 100644
index 0000000..571f343
--- /dev/null
+++ b/truthseeker/static/css/game_ui_lobby.css
@@ -0,0 +1,207 @@
+/* Global properties */
+html {
+    background-color: black;
+    color: white;
+}
+
+:root {
+    --button-background-color: #FF0000;
+}
+
+.multi_player_mode_choice_title, .multi_player_mode_waiting_for_host, .player_name, .players_title, .rounds_count_title, .room_code_text_title, .room_title {
+    font-family: "Titan One", sans-serif;
+    margin-bottom: 0.5em;
+    margin-top: 0.5em;
+}
+
+.join_room_view, .room_view {
+    height: calc(100vh - var(--body-margin) * 2);
+}
+
+/* Action buttons */
+.action_button {
+    border-color: black;
+    border-style: solid;
+    border-width: 0.125em;
+    background-color: var(--button-background-color);
+    border-radius: var(--button-and-dialog-border-radius);
+    color: white;
+    cursor: pointer;
+    font-family: "Titan One", sans-serif;
+    margin-left: auto;
+    margin-right: auto;
+    padding-top: 0.5em;
+    padding-bottom: 0.5em;
+    padding-left: 1em;
+    padding-right: 1em;
+    text-transform: uppercase;
+    overflow: hidden;
+    transition: box-shadow 0.5s, transform 0.5s;
+}
+
+.action_button:hover {
+    transform: translate(0.1em, 0.1em);
+    box-shadow: 10px 10px 0px 0px black;
+}
+
+.multi_player_mode_choice .action_button, .room_code_text .action_button {
+    font-size: 1.5em;
+    min-width: 10em;
+}
+
+/* Room view major elements */
+.room_title {
+    color: var(--button-background-color);
+    font-family: "Spicy Rice", sans-serif;
+    font-weight: bold;
+    font-size: 4em;
+    margin: 0.25em;
+}
+
+.room_view_container {
+    align-items: center;
+    display: flex;
+    flex-direction: row;
+    flex-wrap: wrap;
+    justify-content: space-around;
+}
+
+/* Room code */
+.room_code {
+    color: var(--button-background-color);
+}
+
+.room_code_text {
+    align-items: center;
+    display: flex;
+    flex-direction: column;
+    flex-wrap: nowrap;
+    justify-content: center;
+}
+
+.room_code_text_title {
+    font-size: 2em;
+    margin: 0.25em;
+}
+
+#invite_friends_button {
+    font-size: 1em;
+    text-transform: none;
+    background-color: #c2c0c0;
+    border-radius: 0.5em;
+}
+
+#invite_friends_button:hover {
+    transform: translate(0.1em, 0.1em);
+    box-shadow: 10px 10px 0px 0px black;
+}
+
+/* Waiting for host */
+.multi_player_mode_waiting_for_host {
+    font-size: 2.5em;
+    max-width: 20em;
+    text-align: center;
+}
+
+/* Multi-player mode choice */
+.multi_player_mode_choices {
+    padding: 1em;
+}
+
+.multi_player_mode_choice {
+    display: flex;
+    flex-direction: column;
+    flex-wrap: nowrap;
+    justify-content: center;
+    align-items: center;
+    text-align: center;
+}
+
+.multi_player_mode_choice_title {
+    font-size: 2em;
+    margin: 0.5em;
+}
+
+.multi_player_mode_choice_number {
+    align-items: center;
+    display: flex;
+    flex-direction: row;
+    margin: 0.75em;
+}
+
+/* Rounds count */
+#rounds_count {
+    background-color: white;
+    border: none;
+    border-radius: 0.5em;
+    color: black;
+    font-family: "Titan One", sans-serif;
+    font-size: 1em;
+    padding: 0.5em;
+    width: 2.5em;
+}
+
+.rounds_count_title {
+    font-size: 1.375em;
+    margin: 0.5em;
+}
+
+/* Players list */
+.players_title {
+    align-content: center;
+    align-items: center;
+    display: flex;
+    font-size: 3em;
+    flex-direction: column;
+    flex-wrap: wrap;
+    justify-content: center;
+    margin: 1em;
+}
+
+.player_names {
+    border: 0.25em white solid;
+    border-radius: 0.75em;
+    max-height: 12em;
+    overflow-y: scroll;
+}
+
+.player_name {
+    font-size: 1.5em;
+    margin-bottom: 0.5em;
+    margin-top: 0.5em;
+    text-align: center;
+    color: white;
+}
+
+/* Game join view */
+.join_room_view {
+    align-items: center;
+    display: flex;
+    flex-direction: column;
+    flex-wrap: nowrap;
+    justify-content: center;
+}
+
+#game_username {
+    background-color: white;
+    border: none;
+    border-radius: 0.375em;
+    color: black;
+    font-family: "Titan One", sans-serif;
+    font-size: 1.25em;
+    margin: 0.5em;
+    padding: 0.5em;
+}
+
+#join_game_button {
+    font-size: 1.25em;
+    margin: 1em;
+}
+
+/* Game start failure */
+.game_start_failed {
+    color: var(--button-background-color);
+    font-family: "Roboto Mono", sans-serif;
+    font-weight: bold;
+    font-size: 1em;
+}