html, body {
  padding: 0;
  margin: 0;
  height: 100%;
  width: 100%;
  font-family: Arial, Helvetica, sans-serif;
}

#app {
  height: 100%;
  width: 100%;
  display: flex;
}

#sidebar {
  width: 320px;
  padding: 14px;
  background: #fff;
  border-right: 1px solid #ddd;
  box-sizing: border-box;
}

#sidebar h1 {
  margin: 0 0 12px 0;
  font-size: 28px;
}

#sidebar label {
  display: block;
  margin-top: 10px;
  margin-bottom: 6px;
  font-size: 13px;
  font-weight: 600;
}

#sidebar select {
  width: 100%;
  padding: 8px;
  border: 1px solid #bbb;
  border-radius: 4px;
  box-sizing: border-box;
}

.btn {
  width: 100%;
  margin-top: 10px;
  padding: 10px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-weight: 700;
}

.btn-blue { background: #2b74d8; color: #fff; }
.btn-green { background: #43a047; color: #fff; }
.btn-dark { background: #111; color: #fff; }

hr {
  margin: 16px 0;
  border: none;
  border-top: 1px solid #eee;
}

.tip {
  margin-top: 10px;
  font-size: 12px;
  color: #666;
}

#viewDiv {
  flex: 1;
  height: 100%;
}

/* mobile: stack sidebar on top */
@media (max-width: 900px) {
  #app {
    flex-direction: column;
  }
  #sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid #ddd;
  }
  #viewDiv {
    height: calc(100% - 420px);
  }
}