body {
  font-family: 'Arial', sans-serif;
}

.container {
  max-width: 1024px;
  padding: 15px;
  margin: 0 auto;
  overflow: auto;
}

.header-title {
  text-align: center;
}

.header-title img {
  max-height: 100px;
}

.text p,
.text-root p {
  border: 1px solid #ccc;
  border-radius: 5px;
  padding: 10px;
}

.tests {
  margin: 50px auto 20px;
  float: left;
  width: 50%;
  box-sizing: border-box;
}

.controls {
  margin: 100px auto;
  text-align: center;
  float: left;
  width: 50%;
  box-sizing: border-box;
}

.btn {
  padding: 10px 15px;
  border-radius: 5px;
  background: #fff;
  border: 1px solid #bbb;
  cursor: pointer;
}

.btn:hover {
  background: #e6e6e6;
  border-color: #adadad;
}

.btn:active {
  background: #e6e6e6;
  border-color: #666;
  box-shadow: inset 0 3px 5px rgba(0, 0, 0, 0.125);
  outline: none;
}

.btn:focus {
  outline: none;
}

.responsive,
.replace-str {
  padding: 15px 0;
}

.replace-str-input {
  padding: 10px 15px;
  border-radius: 5px;
  background: #fff;
  border: 1px solid #bbb;
}

.view-on-github {
  text-align: center;
  margin: 20px 0 40px;
}

.view-on-github a,
.view-on-github a:visited,
.view-on-github a:link {
  text-decoration: none;
  color: #000;
}

.view-on-github a img {
  max-height: 20px;
  width: auto;
  position: relative;
  top: 4px;
  left: -2px;
}

@media (max-width: 600px) {
  .tests,
  .controls {
    width: 100%;
    float: none;
  }

  .controls {
    margin: 0;
  }
}