body{
    margin:0;
    width:100%;
    height:100vh;
    display: flex;
    justify-content: center;
    align-items :center;
    font-family: Helvetica, Arial, sans-serif;
}

.piano{
    width:1360px;
    height: 625px;
    margin: 0px;
    display: flex;
    flex-direction:column;
    justify-content:space-between;
    align-items:center;
    background-color: #1a1a1a;
    padding: 5px;
    border-radius: 1px;
}

.piano-bar{
    margin-top: 15px;
    min-width:100%;
    height:40px;
    display: flex;
    justify-content: space-between;
}
.piano-bar-left{
    min-width:26%;
    height:100%;
    flex-direction: row;
}

.piano-bar-mid{
    min-width:500px;
    min-height:80px;
    margin-top: 5px;
    flex-direction: row;
    background-color: #282828;  
    border-radius: 10px;
    box-shadow: inset 0 0 10px #111;
    display: flex;
    justify-content: space-between;
}

.piano-bar-right{
    min-width:26%;
    height:100%;
    flex-direction: row-reverse;
}

.piano-line-left{
    width:98%;
    size:8px;
    border: none;
    margin-left: 0px;
    background-color: rgb(150 138 138 / 23%);
    padding-top:6px;
}

.piano-line-right{
    width:98%;
    size:8px;
    border: none;
    margin-right: 0px;
    background-color: #968a8a3b;
    padding-top:6px;
} 

.piano-bar-mid #off{
    padding-left: 20px!important;
    padding-top: 20px!important;
    font-size:40px;
    color: #7d7b7b;
}

.piano-bar-mid #on{
   visibility: hidden;
   padding-right: 20px!important;
   padding-top: 25px!important;
   font-size:30px;
   color: #7d7b7b;
}

.slider {
    margin-top: 35px;
    margin-left: -10px;
    -webkit-appearance: none;
    width: 175%;
    height: 12px;
    border-radius: 5px;
    background: #7d7b7b;
    outline: none;
    opacity: 0.7;
    -webkit-transition: .2s;
    transition: opacity .2s;
  }
  
  .slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 15px;
    height: 35px;
    border-radius: 5px;
    background: #7d7b7b;
    cursor: pointer;
  }
  
  .slider::-moz-range-thumb {
    width: 15px;
    height: 35px;
    border-radius: 5px;
    background: #7d7b7b;
    cursor: pointer;
  }

  .btn1{
    height: 60%;
    width: 17%;
    text-align: center;
    margin-top: 3%;
    margin-right: -3%;
    background-color: #ffffffe3;

    cursor: pointer;
    text-decoration: none;
    outline: none;
    border: none;
    border-radius: 5px;
    box-shadow: 0 3px #999;
  }

  .btn1:hover,#btnOne:hover{
    background-color: #15c915;
    color:#ffffff;
  }

  .btn1:active,#btnOne:active{
    background-color: #15c915;
    box-shadow: 0 3px #999;
    transform: translateY(0.5px);
  }

  .btn2:hover, #btnTwo:hover{
    background-color: #0f0f0f;
    color:white;
  }
  
  .btn2:active,#btnTwo:active{
    background-color: #0f0f0f;
    box-shadow: 0 3px #999;
    transform: translateY(0.5px);
  }

  .btn2{
    height: 60%;
    width: 16%;
    text-align: center;
    margin-top: 3%;
    margin-right: 3%;
    background-color: #ffffffe3;

    cursor: pointer;
    text-decoration: none;
    outline: none;
    border: none;
    border-radius: 5px;
    box-shadow: 0 3px #999;
  }

  #btnOne{
    font-size:30px;
    color: #12f012;
  }

  #btnTwo{
    font-size:30px;
    color: #080808;
  }

.piano_header{
    width: 100%;
    height:100%;
    display: flex;
    justify-content: space-around;
    align-items: center;
}

.piano_speaker{
    width: 295px;
    height: 150px;
    padding-right: 10px;
    border-radius: 15px;
    background: /* CSS pattern galary */
        radial-gradient(black 15%, transparent 16%) 0 0,
        radial-gradient(black 15%, transparent 16%) 8px 8px,
        radial-gradient(rgba(255,255,255,.1) 15%, transparent 20%) 0 1px,
        radial-gradient(rgba(255,255,255,.1) 15%, transparent 20%) 8px 9px;
    background-color:#282828;
    background-size:16px 16px;
    box-shadow: 0 0 8px 6px #000000bf;
}

.piano_interface{
    width:500px;
    height:200px;
    border-radius: 15px;
    background-color: #282828; 
    box-shadow: inset 0 0 10px #111;
    color:white;
    box-sizing: border-box; 
    padding-left: 20px;
    padding-bottom: 15px;
    padding-top: 10px;
}

.piano_play-btn{
    font-size: 15px;
    padding: 4px 30px;
    height: 27px;
    cursor: pointer;
    text-align: center;
    text-decoration: none;
    outline: none;
    color: #000;
    background-color: #ffffff;
    border: none;
    border-radius: 5px;
    box-shadow: 0 4px #999;
}

.piano_play-btn:hover {background-color: #e8a5a5;}

.piano_play-btn:active {
  background-color: #ffffff;
  box-shadow: 0 3px #666;
  transform: translateY(0.5px);
}

.piano_song_list{
    font-size: 15px;
    width: 150px;
    height: 27px;
    padding: 4px 3px;
    cursor: pointer;
    text-align: left;
    text-decoration: none;
    outline: none;
    color: #000;
    border: none;
    border-radius: 4px;
    box-shadow: 0 4px #999;
}

.piano_tempo{
    font-size: 15px;
    width:90px;
    height: 27px;
    padding: 4px 3px;
    cursor: pointer;
    text-align: left;
    text-decoration: none;
    outline: none;
    color: #000;
    border: none;
    border-radius: 4px;
    box-shadow: 0 4px #999;
}

/* Designing Piano Keyboard */

.piano_keyboard{
    width: 100%;
    height:350px;
    background-color: #000;
    display: flex;  /* Arranging piano keys in Horizontally (row) */
    padding-top: 28px;
    padding-left: 5px;
    padding-right: 5px;
    padding-bottom: 2px;
}

.piano_key{
    width:30px;
    height:100%;
    padding:0;
    margin :0 0.5px;
    background-color: #fff;
    border: 1px solid black;
    box-sizing: border-box;
    flex-grow:1 ; /* it will cover full width of keyboard */
    text-align: center;
    border-radius: 0 0 7px 7px; 
}
/**
Black div must be placed between two white div.and position will be 
relative. & every black key has absolute position.
*/
.empty-space{
    position: relative;
}

.piano_keys-black{
    background-color: #000;
    color:#fff;
    height:60%;
    position: absolute;
    top:0; /* Placing Black key to Top */
    left:-15px;
    font-size: 14px;
}

/* Every black key should be in middle of two white key , so 50% of left white key & 50% of right white key */

.piano_keys-white{
    padding-top: 130px;
    font-size: 14px;
}

.piano_key-playing{
    background-color:#74b9ff ;
}