feat: add multilingual interface support

styles.css

@@ -241,14 +241,49 @@ body {
   height: auto;
 }
 
-.brand-subtitle {
+.brand-footer {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
   margin-top: 8px;
+  /* Extend through the brand's reserved close-button clearance so the gear
+     and sidebar close controls share the same right-hand axis. */
+  margin-right: -60px;
+}
+
+.brand-subtitle {
   color: var(--muted);
   font-size: 1rem;
-  font-weight: 700;
+  font-weight: 400;
   letter-spacing: 0.04em;
 }
 
+.settings-open {
+  display: grid;
+  width: 42px;
+  height: 42px;
+  min-width: 42px;
+  padding: 0;
+  place-items: center;
+  border: 1px solid var(--panel-border);
+  border-radius: 50%;
+  background: rgba(255, 255, 255, 0.55);
+  color: var(--ink);
+  box-shadow: none;
+}
+
+.settings-open:hover,
+.settings-open:focus-visible {
+  background: rgba(31, 122, 98, 0.1);
+  outline: 2px solid rgba(31, 122, 98, 0.25);
+  outline-offset: 2px;
+}
+
+.settings-open .material-symbols-outlined {
+  font-size: 1.3rem;
+}
+
 .visually-hidden {
   position: absolute;
   width: 1px;
@@ -370,6 +405,10 @@ button:disabled {
   color: var(--muted);
 }
 
+.status:empty {
+  display: none;
+}
+
 .status.error {
   color: #9d2e21;
 }
@@ -427,7 +466,12 @@ button:disabled {
   display: none;
 }
 
-.feature-modal {
+.settings-modal[hidden] {
+  display: none;
+}
+
+.feature-modal,
+.settings-modal {
   position: fixed;
   z-index: 20;
   inset: 0;
@@ -436,13 +480,53 @@ button:disabled {
   place-items: center;
 }
 
-.feature-modal-backdrop {
+.feature-modal-backdrop,
+.settings-modal-backdrop {
   position: absolute;
   inset: 0;
   background: rgba(31, 42, 46, 0.35);
   backdrop-filter: blur(1px);
 }
 
+.settings-modal-dialog {
+  position: relative;
+  width: min(100%, 380px);
+  padding: 28px;
+  border: 1px solid var(--panel-border);
+  border-radius: 24px;
+  background: var(--panel);
+  backdrop-filter: blur(16px);
+  box-shadow: var(--shadow);
+}
+
+.settings-modal-close {
+  position: absolute;
+  top: 12px;
+  right: 12px;
+  display: grid;
+  width: 36px;
+  height: 36px;
+  padding: 0;
+  place-items: center;
+  border: 1px solid var(--panel-border);
+  border-radius: 50%;
+  background: transparent;
+  color: var(--ink);
+  box-shadow: none;
+  font-size: 1.5rem;
+  line-height: 1;
+}
+
+.settings-modal-dialog h2 {
+  padding-right: 44px;
+}
+
+.settings-form {
+  display: grid;
+  gap: 20px;
+  margin-top: 24px;
+}
+
 .feature-modal-dialog {
   position: relative;
   width: min(100%, 360px);
@@ -506,9 +590,12 @@ button:disabled {
 }
 
 .feature-details dd {
+  min-width: 0;
   margin: 0;
   font-size: 1.1rem;
   font-weight: 700;
+  overflow-wrap: anywhere;
+  text-align: right;
 }
 
 .feature-inhabited {
@@ -564,7 +651,9 @@ button:disabled {
 }
 
 .feature-association-label {
+  min-width: 0;
   font-weight: 700;
+  overflow-wrap: anywhere;
 }
 
 .feature-association-area {