seahub/frontend/src/css/layout.css

#wrapper {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
}

/* for top bottom layout*/
#header {
  height: 49px;
  display: flex;
}

/* for left right layout */
#main {
  flex: 1;
  display: flex;
}

.side-panel {
  flex: 0 0 25%;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.main-panel {
  flex: 1 0 75%;
  display: flex;
  flex-direction: column;
}

@media (max-width: 767px) {
  .side-panel {
    position:fixed;
    left:-300px;
    z-index:1; /* important! */
    width:300px;
    height:100%;
    background:#f8f8f8;
    -webkit-transition: all 0.3s ease;
    -moz-transition: all 0.3s ease;
    transition: all 0.3s ease;
  }
}

.side-panel-north,
.main-panel-north {
  display: flex;
  flex-shrink: 0;
  padding: .5rem 1rem;
  background: #f4f4f7;
  border-bottom: 1px solid #e8e8e8;
}

.side-panel-center,
.main-panel-center {
  display: flex;
  flex-direction: column;
  flex: 1;
}

.side-panel-center,
.side-panel-footer {
  min-height: 0;
  border-right: 1px solid #eee;
}