Edit in JSFiddle

<div class="example">
   <div class="mt">
    <button class="btn btn-blue btn-raised">Кнопка</button>
    <button class="btn btn-green btn-raised">Кнопка</button>
    <button class="btn btn-orange btn-raised">Кнопка</button>
    <button class="btn btn-red btn-raised">Кнопка</button>
    <button class="btn btn-black btn-raised">Кнопка</button>
    <button class="btn btn-grey btn-raised">Кнопка</button>
    <button class="btn btn-white btn-raised">Кнопка</button>
  </div> 
  <div class="mt">
    <button class="btn btn-blue btn-flat">Кнопка</button>
    <button class="btn btn-green btn-flat">Кнопка</button>
    <button class="btn btn-orange btn-flat">Кнопка</button>
    <button class="btn btn-red btn-flat">Кнопка</button>
    <button class="btn btn-black btn-flat">Кнопка</button>
    <button class="btn btn-grey btn-flat">Кнопка</button>
  </div>
  <div class="mt">
    <button class="btn btn-blue btn-fab"><i class="fa fa-plus"></i></button>
    <button class="btn btn-green btn-fab"><i class="fa fa-plus"></i></button>
    <button class="btn btn-orange btn-fab"><i class="fa fa-plus"></i></button>
    <button class="btn btn-red btn-fab"><i class="fa fa-plus"></i></button>
    <button class="btn btn-black btn-fab"><i class="fa fa-plus"></i></button>
    <button class="btn btn-grey btn-fab"><i class="fa fa-plus"></i></button>
    <button class="btn btn-white btn-fab"><i class="fa fa-plus"></i></button>
  </div>
  <div class="mt">
    <button class="btn btn-blue btn-icon"><i class="fa fa-plus"></i></button>
    <button class="btn btn-green btn-icon"><i class="fa fa-plus"></i></button>
    <button class="btn btn-orange btn-icon"><i class="fa fa-plus"></i></button>
    <button class="btn btn-red btn-icon"><i class="fa fa-plus"></i></button>
    <button class="btn btn-black btn-icon"><i class="fa fa-plus"></i></button>
    <button class="btn btn-grey btn-icon"><i class="fa fa-plus"></i></button>
  </div>
</div>

/*** контейнер демо ***/
.example {
  position: relative;
  padding: 24px;
  border-bottom: 1px solid #ddd; 
  margin:0 auto;
  max-width: 620px;
}
.mt {
margin-top: 12px;
}

/*** Кнопки ***/

.btn {
  z-index: 2;
  display: inline-block;
  vertical-align: top;
  margin: 2px;
  padding: 0;
  border: none;
  border-radius: 2px;
  background-color: transparent;
  font-family: 'Roboto', sans-serif;  
  font-weight: 400;
  text-align: center;
  text-transform: uppercase;
  cursor: pointer; 
  padding-left: 14px;
  padding-right: 14px;
  font-size: 13px;
  font-size: 0.8125rem;
  line-height: 36px;
  -webkit-transition-property: box-shadow;
  -moz-transition-property: box-shadow;
  transition-property: box-shadow;
  -webkit-transition-duration: .5s;
  -moz-transition-duration: .5s;
  transition-duration: .5s;
}
.btn, .btn:hover, .btn:active, .btn:focus {
  text-decoration: none;
  outline: none; 
}
.btn::-moz-focus-inner {
  border: 0;
  padding: 0; 
}
/*** Цвета шрифта кнопок без фона ***/
.btn-flat.btn-red,
.btn-icon.btn-red {
  color: #f44336; 
}

.btn-flat.btn-blue,
.btn-icon.btn-blue {
  color: #2196f3; 
}

.btn-flat.btn-green,
.btn-icon.btn-green {
  color: #4caf50; 
}

.btn-flat.btn-orange,
.btn-icon.btn-orange {
  color: #ff9800; 
}

.btn-flat.btn-grey,
.btn-icon.btn-grey {
  color: #9e9e9e; 
}

.btn-flat.btn-black,
.btn-icon.btn-black {
  color: #000000; 
}

.btn-flat.btn-white,
.btn-icon.btn-white {
  color: #fff; 
}
/*** Тень кнопок ***/
.btn-raised,
.btn-fab {
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}
/*** Изменение при наведении ***/
.btn-raised:hover,
.btn-flat:hover,
.btn-fab:hover,
.btn-icon:hover {
  box-shadow: 0 3px 6px rgba(0, 0, 0, 0.4); 
}
/*** Кнопки с фоном ***/
.btn-raised.btn-red,
.btn-fab.btn-red {
  color: #fff;
  background-color: #f44336; 
}

.btn-raised.btn-blue,
.btn-fab.btn-blue {
  color: #fff;
  background-color: #2196F3; 
}

.btn-raised.btn-green,
.btn-fab.btn-green {
  color: #fff;
  background-color: #4caf50; 
}

.btn-raised.btn-orange,
.btn-fab.btn-orange {
  color: #fff;
  background-color: #ff9800; 
}

.btn-raised.btn-grey,
.btn-fab.btn-grey {
  color: #fff;
  background-color: #9e9e9e; 
}

.btn-raised.btn-black,
.btn-fab.btn-black {
  color: #fff;
  background-color: #000; 
}

.btn-raised.btn-white,
.btn-fab.btn-white {
  color: rgba(0, 0, 0, 0.87);
  background-color: #fff; 
}
/*** Кнопки с иконками ***/
.btn-icon,
.btn-fab {
  border-radius: 50%;
  padding: 0;
  height: 36px;
  width: 36px;
  line-height: 0;  
}