Website notes:

Translation is handled using ODD/EVEN pages in the Main Navigation menu. The 'landing page' is named 'UNO Aviation' and is in the Not Linked section so it doesn't count as odd or even. In the Main Navigation, ODD pages are English, EVEN pages are Portuguese. The CUSTOM CSS contains code that hides either ODD or EVEN navigation links depending on the language selected. The landing page contains two buttons: one links to the English home page and the other links to the Portuguese home page. Once you land on an English page, the CSS hides all EVEN links to the Portuguese pages and visa versa.

Custom CSS is copied here for safekeeping:

/* ADD BOX AROUND ACTIVE NAV ITEM */
#main-navigation .active-link a {
  color: #ffffff !important;
  background-color: #90521d;
  border-radius: .25em;
}
/* ADD BOLD/UNDERLINE TO ACTIVE NAV ITEM FOR MOBILE */
#mobile-navigation a:active, #mobile-navigation .active-link a, #mobile-navigation .folder .active-folder {
  font-weight: bold;
  text-decoration: underline;
}
/* MAKE ANNOUNCEMENT BAR THINNER */
.sqs-announcement-bar {
  height: 1.5em !important;
  margin-top: -.25em !important;
}
/* ADD SHADOWS TO PAGE TITLES */
.page-title {
  text-shadow: 1px 2px 4px #000000; }
/* MAKE BANNER IMAGE NARROWER */
#banner-area {
    height: auto;
    padding-top: 250px;
    padding-bottom: 30px;
}
/* REDUCE PAGE PADDING */
#page-body-wrapper {
    padding-top: 30px;
    padding-bottom: 50px;
}
/* ADD BROWN LINE ABOVE AND BELOW BANNER IMAGE */
#page-thumb {
      border-top: 1px solid #90521d;
    border-bottom: 1px solid #90521d;
}

/* TURN OFF PORTUGUESE LINKS FOR ENGLISH PAGES */
.collection-56e1b567e3214084d69e2ac3 #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56e1b567e3214084d69e2ac3 #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56e1bed7a3360c4beb060ed6 #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56e1bed7a3360c4beb060ed6 #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56f0346840261d8cdb64c123 #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56f0346840261d8cdb64c123 #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56f03450b09f958b0994ce49 #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56f03450b09f958b0994ce49 #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56f4a7db1bbee0efeff52503 #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56f4a7db1bbee0efeff52503 #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56f44212859fd0a64923484f #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56f44212859fd0a64923484f #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56e1c2691bbee05ec6e3e6c8 #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56e1c2691bbee05ec6e3e6c8 #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56f4a725c2ea5119892864ed #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56f4a725c2ea5119892864ed #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56e1bc7845bf21613f2154d1 #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56e1bc7845bf21613f2154d1 #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56e1c24d1bbee05ec6e3e491 #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56e1c24d1bbee05ec6e3e491 #mobile-navigation ul li:nth-child(even) { display: none !important }

.collection-56fae128356fb03913a77a71 #navigation-top nav ul li:nth-child(even) { display: none !important }
.collection-56fae128356fb03913a77a71 #mobile-navigation ul li:nth-child(even) { display: none !important }
/* END OF ENGLISH SECTION */

/* TURN OFF ENGLISH LINKS FOR PORTUGUESE PAGES */
.collection-5704fd83d51cd4379e4de03e #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-5704fd83d51cd4379e4de03e #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-5704ffa2d210b86ec9a522b0 #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-5704ffa2d210b86ec9a522b0 #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-5705007f01dbae8f24d3f32f #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-5705007f01dbae8f24d3f32f #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-570502264c2f85d8a7465784 #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-570502264c2f85d8a7465784 #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-57050522b654f997589d6695 #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-57050522b654f997589d6695 #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-570506872b8ddeb199ef3983 #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-570506872b8ddeb199ef3983 #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-570506b120c647241f7b8613 #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-570506b120c647241f7b8613 #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-5705071537013baa3ac57f31 #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-5705071537013baa3ac57f31 #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-570507650442621c34c2c08c #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-570507650442621c34c2c08c #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-570507d2b6aa60e895c92247 #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-570507d2b6aa60e895c92247 #mobile-navigation ul li:nth-child(odd) { display: none !important }

.collection-570501a22b8ddeb199ef1eda #navigation-top nav ul li:nth-child(odd) { display: none !important }
.collection-570501a22b8ddeb199ef1eda #mobile-navigation ul li:nth-child(odd) { display: none !important }
/* END OF PORTUGUESE SECTION */