diff --git a/src/python/config_files.py b/src/python/config_files.py
index aeeebbe7..b4972f4e 100644
--- a/src/python/config_files.py
+++ b/src/python/config_files.py
@@ -121,6 +121,10 @@ class UISettings(JSONConfigFile):
                 "toggleDebugConsole":  ["Alt+Shift+C"],
                 "reloadConfig":        ["Alt+Shift+R"],
 
+                "zoomIn":    ["Ctrl+Plus", "Ctrl+Shift+Plus"],
+                "zoomOut":   ["Ctrl+Minus", "Ctrl+Shift+Minus"],
+                "zoomReset": ["Ctrl+Equal", "Ctrl+Backspace"],
+
                 "scrollUp":       ["Alt+Up", "Alt+K"],
                 "scrollDown":     ["Alt+Down", "Alt+J"],
                 "scrollPageUp":   ["Alt+Ctrl+Up", "Alt+Ctrl+K", "PageUp"],
diff --git a/src/qml/Base/HCircleProgressBar.qml b/src/qml/Base/HCircleProgressBar.qml
index 192c4632..67447d1b 100644
--- a/src/qml/Base/HCircleProgressBar.qml
+++ b/src/qml/Base/HCircleProgressBar.qml
@@ -3,7 +3,7 @@ import RadialBar 1.0
 
 RadialBar {
     id: bar
-    implicitWidth: 96
+    implicitWidth: 96 * (theme ? theme.uiScale : 1)
     implicitHeight: implicitWidth
     foregroundColor: theme.controls.circleProgressBar.background
     progressColor: theme.controls.circleProgressBar.foreground
diff --git a/src/qml/Base/HIcon.qml b/src/qml/Base/HIcon.qml
index 8717a526..87f36d4b 100644
--- a/src/qml/Base/HIcon.qml
+++ b/src/qml/Base/HIcon.qml
@@ -14,7 +14,13 @@ Image {
 
 
     property string svgName: ""
-    property int dimension: 20
+
+    property bool small: false
+    property int dimension:
+        theme ?
+        (small ? theme.icons.smallDimension : theme.icons.dimension) :
+        (small ? 16 : 22)
+
     property color colorize: theme.icons.colorize
     property string iconPack: theme ? theme.icons.preferredPack : "thin"
 
diff --git a/src/qml/Base/HImage.qml b/src/qml/Base/HImage.qml
index 1594fd61..700ac301 100644
--- a/src/qml/Base/HImage.qml
+++ b/src/qml/Base/HImage.qml
@@ -80,7 +80,6 @@ Image {
         anchors.centerIn: parent
         visible: broken || image.status === Image.Error
         svgName: "broken-image"
-        dimension: Math.max(16, Math.min(parent.width, parent.height) * 0.2)
         colorize: theme.colors.negativeBackground
     }
 }
diff --git a/src/qml/Base/HTile.qml b/src/qml/Base/HTile.qml
index e4aa678c..ee1eb637 100644
--- a/src/qml/Base/HTile.qml
+++ b/src/qml/Base/HTile.qml
@@ -55,7 +55,8 @@ HButton {
 
                     visible: Layout.maximumWidth > 0
                     Layout.maximumWidth:
-                        text && tile.width >= 160 ? implicitWidth : 0
+                        text && tile.width >= 160 * theme.uiScale ?
+                        implicitWidth : 0
 
                     Behavior on Layout.maximumWidth { HNumberAnimation {} }
                 }
diff --git a/src/qml/Base/HUserAvatar.qml b/src/qml/Base/HUserAvatar.qml
index 42bddb68..1ced9fe1 100644
--- a/src/qml/Base/HUserAvatar.qml
+++ b/src/qml/Base/HUserAvatar.qml
@@ -21,7 +21,7 @@ HAvatar {
         z: 100
 
         sourceComponent: HIcon {
-            dimension: 16
+            small: true
             svgName: "user-power-" + (admin ? "100" : "50")
             colorize: admin ?
                       theme.chat.roomSidePane.member.adminIcon :
diff --git a/src/qml/Base/MediaPlayer/OSDButton.qml b/src/qml/Base/MediaPlayer/OSDButton.qml
index 47100f3d..90bf8b96 100644
--- a/src/qml/Base/MediaPlayer/OSDButton.qml
+++ b/src/qml/Base/MediaPlayer/OSDButton.qml
@@ -4,5 +4,5 @@ import "../../Base"
 
 HButton {
     backgroundColor: "transparent"
-    iconItem.dimension: theme.mediaPlayer.controls.iconHeight
+    iconItem.dimension: theme.mediaPlayer.controls.iconSize
 }
diff --git a/src/qml/Chat/Banners/Banner.qml b/src/qml/Chat/Banners/Banner.qml
index 1145aab7..45bd8fac 100644
--- a/src/qml/Chat/Banners/Banner.qml
+++ b/src/qml/Chat/Banners/Banner.qml
@@ -42,7 +42,6 @@ Rectangle {
 
             HIcon {
                 id: bannerIcon
-                dimension: bannerLabel.implicitHeight
                 visible: Boolean(svgName)
 
                 Layout.leftMargin: theme.spacing / 2
diff --git a/src/qml/Chat/Chat.qml b/src/qml/Chat/Chat.qml
index 93a4e659..4aaa0b39 100644
--- a/src/qml/Chat/Chat.qml
+++ b/src/qml/Chat/Chat.qml
@@ -55,7 +55,7 @@ HPage {
     HLoader {
         source: ready ? "ChatSplitView.qml" : "../Base/HBusyIndicator.qml"
 
-        Layout.preferredWidth: ready ? -1 : 96
+        Layout.preferredWidth: ready ? -1 : 96 * theme.uiScale
         Layout.preferredHeight: Layout.preferredWidth
         Layout.fillWidth: ready
         Layout.fillHeight: ready
diff --git a/src/qml/Chat/RoomHeader.qml b/src/qml/Chat/RoomHeader.qml
index 5a662acd..8c0fd203 100644
--- a/src/qml/Chat/RoomHeader.qml
+++ b/src/qml/Chat/RoomHeader.qml
@@ -93,7 +93,6 @@ Rectangle {
                 HButton {
                     backgroundColor: "transparent"
                     icon.name: "room-view-" + modelData
-                    iconItem.dimension: 22
                     height: parent.height
                     spacing: theme.spacing / 1.5
                     topPadding: 0
diff --git a/src/qml/Chat/RoomSidePane/MembersView.qml b/src/qml/Chat/RoomSidePane/MembersView.qml
index 9165a9db..ecb348c2 100644
--- a/src/qml/Chat/RoomSidePane/MembersView.qml
+++ b/src/qml/Chat/RoomSidePane/MembersView.qml
@@ -50,17 +50,19 @@ HColumnLayout {
             placeholderText: qsTr("Filter members")
             backgroundColor: theme.chat.roomSidePane.filterMembers.background
             bordered: false
+            opacity: width >= 16 ? 1 : 0
 
             onTextChanged: filterLimiter.restart()
 
             Layout.fillWidth: true
             Layout.fillHeight: true
+
+            Behavior on opacity { HOpacityAnimator {} }
         }
 
         HButton {
             enabled: false  // TODO
             icon.name: "room-send-invite"
-            iconItem.dimension: parent.height - 10
             topPadding: 0
             bottomPadding: 0
             toolTip.text: qsTr("Invite to this room")
diff --git a/src/qml/Chat/Timeline/EventContent.qml b/src/qml/Chat/Timeline/EventContent.qml
index 5e6cb86a..ac08e6c8 100644
--- a/src/qml/Chat/Timeline/EventContent.qml
+++ b/src/qml/Chat/Timeline/EventContent.qml
@@ -49,8 +49,12 @@ HRowLayout {
         opacity: collapseAvatar ? 0 : 1
         visible: ! hideAvatar
 
-        Layout.minimumWidth: 58
-        Layout.minimumHeight: collapseAvatar ? 1 : smallAvatar ? 28 : 58
+        Layout.minimumWidth: theme.chat.message.avatarSize
+        Layout.minimumHeight:
+            collapseAvatar ? 1 :
+            smallAvatar    ? theme.chat.message.collapsedAvatarSize :
+            Layout.minimumWidth
+
         Layout.maximumWidth: Layout.minimumWidth
         Layout.maximumHeight: Layout.minimumHeight
         Layout.alignment: Qt.AlignTop
@@ -61,7 +65,7 @@ HRowLayout {
             displayName: model.sender_name
             mxc: model.sender_avatar
             width: parent.width
-            height: collapseAvatar ? 1 : 58
+            height: collapseAvatar ? 1 : theme.chat.message.avatarSize
         }
     }
 
diff --git a/src/qml/Pages/AccountSettings/AccountSettings.qml b/src/qml/Pages/AccountSettings/AccountSettings.qml
index 02ecc09a..5edd3911 100644
--- a/src/qml/Pages/AccountSettings/AccountSettings.qml
+++ b/src/qml/Pages/AccountSettings/AccountSettings.qml
@@ -7,7 +7,7 @@ import "../../utils.js" as Utils
 HPage {
     id: accountSettings
 
-    property int avatarPreferredSize: 256
+    property int avatarPreferredSize: 256 * theme.uiScale
 
     property string userId: ""
 
diff --git a/src/qml/Pages/AccountSettings/Profile.qml b/src/qml/Pages/AccountSettings/Profile.qml
index 62c9556d..fd16c77e 100644
--- a/src/qml/Pages/AccountSettings/Profile.qml
+++ b/src/qml/Pages/AccountSettings/Profile.qml
@@ -95,7 +95,7 @@ HGridLayout {
                     svgName: "upload-avatar"
                     colorize: (! avatar.mxc && overlayHover.hovered) ?
                               theme.colors.accentText : theme.icons.colorize
-                    dimension: 64
+                    dimension: avatar.width / 3
 
                     Layout.alignment: Qt.AlignCenter
                 }
diff --git a/src/qml/Pages/SignIn.qml b/src/qml/Pages/SignIn.qml
index 52920994..343500b1 100644
--- a/src/qml/Pages/SignIn.qml
+++ b/src/qml/Pages/SignIn.qml
@@ -101,7 +101,6 @@ HPage {
 
                 HButton {
                     icon.name: modelData
-                    iconItem.dimension: 24
                     circle: true
                     checked: loginWith == modelData
                     enabled: modelData == "username"
diff --git a/src/qml/Shortcuts.qml b/src/qml/Shortcuts.qml
index 066ce12c..704e3b26 100644
--- a/src/qml/Shortcuts.qml
+++ b/src/qml/Shortcuts.qml
@@ -33,6 +33,21 @@ HShortcutHandler {
         onPressed: py.loadSettings(() => { mainUI.pressAnimation.start() })
     }
 
+    HShortcut {
+        sequences: settings.keys.zoomIn
+        onPressed: theme.uiScale += 0.1
+    }
+
+    HShortcut {
+        sequences: settings.keys.zoomOut
+        onPressed: theme.uiScale = Math.max(0.1, theme.uiScale - 0.1)
+    }
+
+    HShortcut {
+        sequences: settings.keys.zoomReset
+        onPressed: theme.uiScale = 1
+    }
+
     // Pages
 
     HShortcut {
diff --git a/src/qml/SidePane/AccountDelegate.qml b/src/qml/SidePane/AccountDelegate.qml
index 8c1e4e6b..485e4bfc 100644
--- a/src/qml/SidePane/AccountDelegate.qml
+++ b/src/qml/SidePane/AccountDelegate.qml
@@ -58,7 +58,7 @@ HTileDelegate {
 
     HButton {
         id: addChat
-        iconItem.dimension: 16
+        iconItem.small: true
         icon.name: "add-chat"
         backgroundColor: "transparent"
         toolTip.text: qsTr("Add new chat")
@@ -80,7 +80,7 @@ HTileDelegate {
     HButton {
         id: expand
         loading: ! model.data.first_sync_done || ! model.data.profile_updated
-        iconItem.dimension: addChat.iconItem.dimension
+        iconItem.small: true
         icon.name: "expand"
         backgroundColor: "transparent"
         toolTip.text: collapsed ? qsTr("Expand") : qsTr("Collapse")
diff --git a/src/themes/Default.qpl b/src/themes/Default.qpl
index ef6c2f58..a900ce3a 100644
--- a/src/themes/Default.qpl
+++ b/src/themes/Default.qpl
@@ -2,11 +2,7 @@
 
 // Base variables
 
-real uiScale: 1.0  /* TODO: Implement correctly, do not change for now */
-real fontScale: uiScale
-
-Behavior on uiScale   { HNumberAnimation {} }
-Behavior on fontScale { HNumberAnimation {} }
+real uiScale: 1.0
 
 int minimumSupportedWidth:  240 * uiScale
 int minimumSupportedHeight: 120 * uiScale
@@ -17,19 +13,19 @@ int minimumSupportedHeightPlusSpacing: minimumSupportedHeight + spacing * 2
 
 int baseElementsHeight:       36 * uiScale
 int spacing:                  12 * uiScale
-int radius:                   5
+int radius:                   5 * uiScale
 int animationDuration:        100
 real loadingElementsOpacity:  0.8
 real disabledElementsOpacity: 0.3
 
 
 fontSize:
-    int smaller: 13 * fontScale
-    int small:   13 * fontScale
-    int normal:  16 * fontScale
-    int big:     22 * fontScale
-    int bigger:  32 * fontScale
-    int biggest: 48 * fontScale
+    int smaller: 13 * uiScale
+    int small:   13 * uiScale
+    int normal:  16 * uiScale
+    int big:     22 * uiScale
+    int bigger:  32 * uiScale
+    int biggest: 48 * uiScale
 
 fontFamily:
     string sans:  "Roboto"
@@ -94,6 +90,9 @@ icons:
     color colorize:         hsluv(0, 0, colors.intensity * 90)
     color disabledColorize: "white"
 
+    int smallDimension: 16 * uiScale
+    int dimension: 22 * uiScale
+
 
 // Generic UI controls
 
@@ -318,6 +317,9 @@ chat:
         color background:               "transparent"
 
     message:
+        int avatarSize:          58 * uiScale
+        int collapsedAvatarSize: 28 * uiScale
+
         int radius:          theme.radius
         color background:    colors.strongBackground
         color ownBackground: hsluv(
@@ -408,7 +410,7 @@ mediaPlayer:
         color background:  hsluv(0, 0, 0, 0.5)
 
     controls:
-        int iconHeight:        20
+        int iconSize:          icons.dimension
         int volumeSliderWidth: 100
         int speedSliderWidth:  100
         color background:      hsluv(