diff --git a/vendor/clouds3d.js b/vendor/clouds3d.js
index 6003a5f..d94a81f 100644
--- a/vendor/clouds3d.js
+++ b/vendor/clouds3d.js
@@ -13,6 +13,14 @@
 // Progress and build diagnostics are only interesting while the debug panel
 // is on; a wall display must not fill the console with them.
 var DEBUG_LOG = !!(window.CONFIG && window.CONFIG.debug);
+var BASE_PATH = (function () {
+    var p = window.location.pathname || '/';
+    if (p.charAt(p.length - 1) !== '/') {
+        var i = p.lastIndexOf('/');
+        p = i >= 0 ? p.substring(0, i + 1) : '/';
+    }
+    return p;
+})();
 function dbgLog() {
     if (DEBUG_LOG) console.log.apply(console, arguments);
 }
@@ -1408,7 +1416,7 @@ var GROUND_STYLE = GROUND_STYLE_CFG === 'satellite' ? 'satellite' : 'streets';
 var GROUND_TILE_DIRECT = (GROUND_STYLE === 'satellite')
     ? 'https://server.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer/tile/'
     : 'https://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer/tile/';
-var GROUND_TILE_PROXY = (GROUND_STYLE === 'satellite') ? '/esri/imagery/' : '/esri/streets/';
+var GROUND_TILE_PROXY = BASE_PATH + (GROUND_STYLE === 'satellite' ? 'esri/imagery/' : 'esri/streets/');
 // direct by default: works from any origin, including a plain file:// open
 var GROUND_TILE_URL = GROUND_TILE_DIRECT;
 var GROUND_TILE_ID_PREFIX = GROUND_STYLE === 'satellite' ? 'sat/' : '';
@@ -2127,7 +2135,7 @@ var ELEV_UNIT_PX = 256 / ELEV_TILES_PER;  // canvas px per z11 tile
 // elevation-tiles-prod (AWS) answers cross-origin GETs with CORS, so the
 // DEM also loads without our server; /terrarium/ is preferred when present.
 var ELEV_TILE_DIRECT = 'https://s3.amazonaws.com/elevation-tiles-prod/terrarium/';
-var ELEV_TILE_PROXY = '/terrarium/';
+var ELEV_TILE_PROXY = BASE_PATH + 'terrarium/';
 var ELEV_TILE_URL = ELEV_TILE_DIRECT;
 // (the probe needs both URL pairs assigned, so it runs here, not at the
 // ground-source block)
@@ -3184,14 +3192,14 @@ var OP_PUBLIC = [
     'https://overpass-api.de/api/interpreter',
     'https://maps.mail.ru/osm/tools/overpass/api/interpreter'
 ];
-var OP_PROXY = ['/overpass/api/interpreter', '/overpass/mail/interpreter'];
+var OP_PROXY = [BASE_PATH + 'overpass/api/interpreter', BASE_PATH + 'overpass/mail/interpreter'];
 var CAR_ENDPOINTS = OP_PUBLIC.slice();
 var _opProxyChecked = false;
 function opProbeProxy() {
     if (_opProxyChecked) return;
     _opProxyChecked = true;
     if (location.protocol === 'file:') return;
-    fetch('/overpass/api/interpreter', {
+    fetch(OP_PROXY[0], {
         method: 'POST',
         headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
         body: 'data=' + encodeURIComponent('[out:json][timeout:5];out;')