diff --git a/app/src/App.css b/app/src/App.css
new file mode 100644
index 0000000..5804fcd
--- /dev/null
+++ b/app/src/App.css
@@ -0,0 +1,87 @@
+@font-face {
+  font-family: "CascadiaCode";
+  src: url("./assets/fonts/CaskaydiaCoveNerdFont-Regular.ttf")
+    format("truetype");
+  font-weight: normal;
+  font-style: normal;
+}
+@font-face {
+  font-family: "CascadiaCode";
+  src: url("./assets/fonts/CaskaydiaCoveNerdFont-Bold.ttf") format("truetype");
+  font-weight: bold;
+  font-style: normal;
+}
+
+:root {
+  font-family: "CascadiaCode", monospace;
+  font-size: 16px;
+  overflow: hidden;
+
+  --color-bg-base: #1c2128;
+  --color-bg-elevated: #22272e;
+
+  --color-border-subtle: #2d333b;
+  --color-border-muted: #444c56;
+  --color-border-deep: #111;
+
+  --color-text-primary: #adbac7;
+  --color-text-secondary: #768390;
+  --color-text-emphasis: #cdd9e5;
+
+  --color-accent: #b39cd0;
+  --color-accent-hover: rgba(179, 156, 208, 0.85);
+  --color-accent-text-on: #1c2128;
+
+  --color-success: #4ade80;
+  --color-error: #d47373;
+  --color-error-bg: rgba(212, 115, 115, 0.05);
+  --color-error-bg-strong: rgba(212, 115, 115, 0.1);
+  --color-error-border: rgba(212, 115, 115, 0.15);
+
+  --color-shadow-key: rgba(0, 0, 0, 0.3);
+  --color-spinner-track: rgba(28, 33, 40, 0.2);
+
+  color: var(--color-text-primary);
+  background-color: var(--color-bg-base);
+}
+
+body {
+  margin: 0;
+  padding: 0;
+  height: 100vh;
+  width: 100vw;
+  display: flex;
+  justify-content: center;
+  align-items: flex-start;
+  background-color: var(--color-bg-base);
+}
+
+.app-container {
+  width: 28.125rem;
+  height: 37.5rem;
+  box-sizing: border-box;
+  padding: 1.5rem;
+  display: flex;
+  flex-direction: column;
+  background: var(--color-bg-base);
+  border: 1px solid var(--color-border-subtle);
+  overflow-y: auto;
+  overflow-x: hidden;
+}
+
+.app-container::-webkit-scrollbar {
+  width: 0.375rem;
+}
+
+.app-container::-webkit-scrollbar-track {
+  background: transparent;
+}
+
+.app-container::-webkit-scrollbar-thumb {
+  background: var(--color-border-subtle);
+  border-radius: 0.1875rem;
+}
+
+.app-container::-webkit-scrollbar-thumb:hover {
+  background: var(--color-border-muted);
+}
diff --git a/app/src/App.module.css b/app/src/App.module.css
new file mode 100644
index 0000000..7cb1db0
--- /dev/null
+++ b/app/src/App.module.css
@@ -0,0 +1,34 @@
+.header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 1.25rem;
+  padding-bottom: 0.75rem;
+  border-bottom: 1px solid var(--color-bg-elevated);
+}
+
+.logo-section {
+  display: flex;
+  align-items: center;
+  gap: 0.625rem;
+}
+
+.logo-icon {
+  width: 1.5rem;
+  height: 1.5rem;
+  background: var(--color-accent);
+  border-radius: 0.25rem;
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  color: var(--color-accent-text-on);
+  font-weight: 700;
+  font-size: 1rem;
+}
+
+.logo-title {
+  font-size: 1.15rem;
+  font-weight: bold;
+  letter-spacing: 0.2px;
+  color: var(--color-text-emphasis);
+}
diff --git a/app/src/assets/fonts/CaskaydiaCoveNerdFont-Bold.ttf b/app/src/assets/fonts/CaskaydiaCoveNerdFont-Bold.ttf
new file mode 100644
index 0000000..d7ec691
Binary files /dev/null and b/app/src/assets/fonts/CaskaydiaCoveNerdFont-Bold.ttf differ
diff --git a/app/src/assets/fonts/CaskaydiaCoveNerdFont-Regular.ttf b/app/src/assets/fonts/CaskaydiaCoveNerdFont-Regular.ttf
new file mode 100644
index 0000000..b1d98df
Binary files /dev/null and b/app/src/assets/fonts/CaskaydiaCoveNerdFont-Regular.ttf differ
diff --git a/app/src/components/GeneralTab.module.css b/app/src/components/GeneralTab.module.css
new file mode 100644
index 0000000..bd5e3df
--- /dev/null
+++ b/app/src/components/GeneralTab.module.css
@@ -0,0 +1,73 @@
+.hotkey-display-group {
+  display: flex;
+  align-items: center;
+  cursor: pointer;
+  padding: 0.5rem;
+  border-radius: 0.25rem;
+  background: var(--color-bg-base);
+  border: 1px solid var(--color-border-subtle);
+  transition: all 0.2s;
+}
+
+.hotkey-display-group:hover {
+  border-color: var(--color-accent);
+  background: var(--color-bg-elevated);
+}
+
+.hotkey-display-group.disabled {
+  opacity: 0.4;
+  cursor: not-allowed;
+  background-color: var(--color-bg-base);
+}
+
+.hotkey-display-group.disabled:hover {
+  border-color: var(--color-border-subtle);
+  background: var(--color-bg-base);
+}
+
+.hotkey-display-group.recording {
+  background: var(--color-error-bg-strong);
+  border-color: var(--color-error);
+  color: var(--color-error);
+  animation: pulse-red 1.5s infinite;
+}
+
+.key-cap {
+  background-color: var(--color-bg-elevated);
+  border: 1px solid var(--color-border-muted);
+  border-bottom: 0.125rem solid var(--color-border-deep);
+  border-radius: 0.1875rem;
+  padding: 0.125rem 0.375rem;
+  font-family: "CascadiaCode", monospace;
+  font-size: 0.75rem;
+  color: var(--color-text-primary);
+  box-shadow: 0 1px 0 var(--color-shadow-key);
+}
+
+.key-plus {
+  color: var(--color-text-secondary);
+  margin: 0 0.25rem;
+  font-weight: bold;
+}
+
+.conflict-warning {
+  margin-top: 0.5rem;
+  font-size: 0.75rem;
+  color: var(--color-error);
+  background: var(--color-error-bg);
+  border: 1px solid var(--color-error-border);
+  padding: 0.375rem 0.625rem;
+  border-radius: 0.25rem;
+}
+
+@keyframes pulse-red {
+  0% {
+    opacity: 0.8;
+  }
+  50% {
+    opacity: 1;
+  }
+  100% {
+    opacity: 0.8;
+  }
+}
diff --git a/app/src/components/LicenseTab.module.css b/app/src/components/LicenseTab.module.css
new file mode 100644
index 0000000..a2fc87b
--- /dev/null
+++ b/app/src/components/LicenseTab.module.css
@@ -0,0 +1,129 @@
+.license-active {
+  color: var(--color-success);
+}
+
+.license-unregistered {
+  color: var(--color-error);
+}
+
+.license-activation-area {
+  display: flex;
+  flex-direction: column;
+  gap: 0.5rem;
+  padding-bottom: 1rem;
+}
+
+.license-input-group {
+  display: flex;
+  gap: 0.5rem;
+}
+
+.license-input {
+  flex-grow: 1;
+  background: var(--color-bg-base);
+  border: 1px solid var(--color-border-subtle);
+  color: var(--color-text-emphasis);
+  padding: 0.375rem 0.625rem;
+  border-radius: 0.25rem;
+  font-family: inherit;
+  font-size: 0.8rem;
+  outline: none;
+}
+
+.license-input:focus {
+  border-color: var(--color-accent);
+}
+
+.license-input:disabled {
+  opacity: 0.5;
+  cursor: not-allowed;
+}
+
+.activate-btn {
+  background: var(--color-accent);
+  border: none;
+  color: var(--color-accent-text-on);
+  padding: 0.375rem 0.75rem;
+  border-radius: 0.25rem;
+  cursor: pointer;
+  font-weight: bold;
+  font-family: inherit;
+  transition: background 0.15s;
+}
+
+.activate-btn:hover {
+  background: var(--color-accent-hover);
+}
+
+.activate-btn:disabled {
+  opacity: 0.6;
+  cursor: not-allowed;
+}
+
+.error-text {
+  font-size: 0.75rem;
+  color: var(--color-error);
+  margin-top: 0.25rem;
+}
+
+.hwid-container {
+  display: flex;
+  flex-direction: column;
+  gap: 0.25rem;
+  background: var(--color-bg-base);
+  padding: 0.625rem;
+  border-radius: 0.25rem;
+  border: 1px solid var(--color-border-subtle);
+  margin: 0.5rem 0;
+}
+
+.hwid-label {
+  font-size: 0.7rem;
+  color: var(--color-text-secondary);
+  text-transform: uppercase;
+}
+
+.hwid-val {
+  font-family: "CascadiaCode", monospace;
+  font-size: 0.75rem;
+  color: var(--color-text-primary);
+  word-break: break-all;
+}
+
+.spinner-container {
+  display: flex;
+  align-items: center;
+  gap: 0.375rem;
+  justify-content: center;
+}
+
+.spinner {
+  width: 0.875rem;
+  height: 0.875rem;
+  border: 0.125rem solid var(--color-spinner-track);
+  border-top-color: var(--color-accent-text-on);
+  border-radius: 50%;
+  animation: spin 0.8s linear infinite;
+}
+
+@keyframes spin {
+  to {
+    transform: rotate(360deg);
+  }
+}
+
+.offline-toggle {
+  background: none;
+  border: none;
+  color: var(--color-text-secondary);
+  font-size: 0.75rem;
+  cursor: pointer;
+  padding: 0;
+  text-align: left;
+  font-family: inherit;
+}
+
+.offline-toggle:hover {
+  color: var(--color-accent);
+  text-decoration: underline;
+}
diff --git a/app/src/components/RulesTab.module.css b/app/src/components/RulesTab.module.css
new file mode 100644
index 0000000..4cc56f6
--- /dev/null
+++ b/app/src/components/RulesTab.module.css
@@ -0,0 +1,50 @@
+.input-row {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  margin-top: 0.5rem;
+}
+
+.custom-params-input {
+  width: 20rem;
+  padding: 0.375rem 0.625rem;
+  font-size: 0.8rem;
+  background: var(--color-bg-base);
+  border: 1px solid var(--color-border-muted);
+  border-radius: 0.25rem;
+  color: var(--color-text-primary);
+}
+
+.custom-params-input:focus {
+  outline: none;
+  border-color: var(--color-accent);
+}
+
+.custom-params-input::placeholder {
+  color: var(--color-text-secondary);
+  opacity: 0.6;
+}
+
+.save-indicator {
+  font-size: 0.75rem;
+  white-space: nowrap;
+}
+
+.save-indicator--debouncing {
+  color: var(--color-text-secondary);
+}
+
+.save-indicator--saved {
+  color: var(--color-accent);
+  animation: fade-out 1.5s ease forwards;
+}
+
+@keyframes fade-out {
+  0%,
+  70% {
+    opacity: 1;
+  }
+  100% {
+    opacity: 0;
+  }
+}
diff --git a/app/src/components/SettingsLayout.module.css b/app/src/components/SettingsLayout.module.css
new file mode 100644
index 0000000..58a2ac6
--- /dev/null
+++ b/app/src/components/SettingsLayout.module.css
@@ -0,0 +1,54 @@
+.section {
+  display: flex;
+  flex-direction: column;
+  gap: 0.75rem;
+  margin-bottom: 1.25rem;
+}
+
+.section-title {
+  font-size: 0.75rem;
+  font-weight: bold;
+  text-transform: uppercase;
+  color: var(--color-text-secondary);
+  letter-spacing: 1.5px;
+}
+
+.settings-list {
+  background: var(--color-bg-elevated);
+  border: 1px solid var(--color-border-subtle);
+  border-radius: 0.375rem;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+}
+
+.settings-row {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 0.75rem 1rem;
+  border-bottom: 1px solid var(--color-border-subtle);
+}
+
+.settings-row:last-child {
+  border-bottom: none;
+}
+
+.settings-info {
+  display: flex;
+  flex-direction: column;
+  gap: 0.125rem;
+  padding-right: 0.75rem;
+}
+
+.settings-name {
+  font-weight: 500;
+  font-size: 0.9rem;
+  color: var(--color-text-primary);
+}
+
+.settings-desc {
+  font-size: 0.75rem;
+  color: var(--color-text-secondary);
+  line-height: 1.3;
+}
diff --git a/app/src/components/TabHeaders.module.css b/app/src/components/TabHeaders.module.css
new file mode 100644
index 0000000..5b45d88
--- /dev/null
+++ b/app/src/components/TabHeaders.module.css
@@ -0,0 +1,46 @@
+.tab-headers {
+  display: flex;
+  gap: 1rem;
+  border-bottom: 1px solid var(--color-border-subtle);
+  margin-bottom: 1.25rem;
+}
+
+.tab-btn {
+  background: transparent;
+  border: none;
+  color: var(--color-text-secondary);
+  padding: 0.375rem 0.25rem;
+  cursor: pointer;
+  font-weight: 500;
+  font-family: inherit;
+  position: relative;
+  transition: color 0.15s;
+}
+
+.tab-btn:hover {
+  color: var(--color-text-primary);
+}
+
+.tab-btn:disabled {
+  opacity: 0.35;
+  cursor: not-allowed;
+}
+
+.tab-btn:disabled:hover {
+  color: var(--color-text-secondary);
+}
+
+.tab-btn.active {
+  color: var(--color-accent);
+  font-weight: bold;
+}
+
+.tab-btn.active::after {
+  content: "";
+  position: absolute;
+  bottom: -1px;
+  left: 0;
+  right: 0;
+  height: 0.125rem;
+  background-color: var(--color-accent);
+}
diff --git a/app/src/components/ToggleSwitch.module.css b/app/src/components/ToggleSwitch.module.css
new file mode 100644
index 0000000..ca2f6b3
--- /dev/null
+++ b/app/src/components/ToggleSwitch.module.css
@@ -0,0 +1,62 @@
+.switch {
+  position: relative;
+  display: inline-block;
+  width: 2.25rem;
+  height: 1.125rem;
+  flex-shrink: 0;
+}
+
+.switch input {
+  opacity: 0;
+  width: 0;
+  height: 0;
+}
+
+.slider {
+  position: absolute;
+  cursor: pointer;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  background-color: var(--color-bg-base);
+  border: 1px solid var(--color-border-muted);
+  border-radius: 0.1875rem;
+  transition: 0.15s;
+}
+
+.slider:before {
+  position: absolute;
+  content: "";
+  height: 0.75rem;
+  width: 0.75rem;
+  left: 0.125rem;
+  bottom: 0.125rem;
+  background-color: var(--color-text-secondary);
+  transition: 0.15s;
+  border-radius: 1px;
+}
+
+.switch input:checked + .slider {
+  background-color: var(--color-bg-base);
+  border-color: var(--color-accent);
+}
+
+.switch input:checked + .slider:before {
+  transform: translateX(1.125rem);
+  background-color: var(--color-accent);
+}
+
+.switch input:disabled + .slider {
+  opacity: 0.35;
+  cursor: not-allowed;
+}
+
+.switch input:disabled + .slider:before {
+  cursor: not-allowed;
+}
+
+.switch input:focus-visible + .slider {
+  outline: 0.125rem solid var(--color-accent);
+  outline-offset: 0.125rem;
+}