MediaWiki:Common.css

:root {
  --body-main:           #e2dbc8;
  --body-light:          #d8ccb4;
  --body-mid:            #d0bd97;    /* needed by your .vectorTabs > li > a */
  --body-border:         #94866d;    /* needed by your borders */
  --background-link-color: #52351e;  /* needed for your tab text color */
  --ooui-normal-border:  #b8a282;
}

body {
  background: var(--body-main) url('/resources/assets/bg.png') no-repeat center top fixed;
  background-size: cover;
}

#mw-head {
  position: relative;
  overflow: hidden;
}
#mw-head::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0; height: 250px;
  background: linear-gradient(
    to bottom,
    rgba(226,219,200,0.95) 0%,
    rgba(226,219,200,0)    100%
  );
  pointer-events: none;
  z-index: 1;
}
#mw-head .mw-head-logo,
#mw-head .vector-menu {
  position: relative;
  z-index: 2;
}

.vectorTabs {
  background: var(--body-main);
  border-bottom: none;
  margin-bottom: 0;
  padding: 0 0.5em;
  border-radius: 0.5em 0.5em 0 0;
}
.vectorTabs > li > a {
  background: var(--body-mid);
  color:     var(--background-link-color);
  border:    1px solid var(--body-border);
  border-bottom: none;
  border-radius: 0.5em 0.5em 0 0;
  margin-right: -1px;
  padding:       0.5em 1em;
}
.vectorTabs > li.tabselected > a {
  background: #fff;
  border-bottom: 1px solid #fff;
}

#content,
#bodyContent {
  background: #fff;
  border:     1px solid var(--body-border);
  border-radius: 0 0 0.5em 0.5em;
  padding:        1em;
  margin-top:    -1px;
}