index.css

body {
    margin: 0;
}

@font-face {
    src: url(Karla-Regular.ttf);
    font-family: "Karla";
}

@font-face {
    src: url(Inter-Regular.otf);
    font-family: 'Inter';
}

.pw-generator{
    width: 550px;
    height: 550px;
    background: #1F2937;
    margin: 0 auto;
    padding: 115px 0 0 52px;
}

.heading {
    font-family: 'Karla';
    font-style: normal;
    font-weight: 800;
    font-size: 40px;
    line-height: 40px;
    letter-spacing: -0.025em;
    color: #FFFFFF;
    width: 354px;
    height: 80px;
}

span {
    color: #4ADF86;
}

h2 {
    font-family: 'Inter';
    font-style: normal;
    font-weight: 400;
    font-size: 20px;
    line-height: 28px;
    color: #D5D4D8;
}

button {
    width: 191px;
    height: 42px;
    background: #10B981;
    box-shadow: 0px 1px 2px rgba(0, 0, 0, 0.05);
    border-radius: 6px;
    border: none;
    padding: 9px 17px 9px 15px;
    font-family: 'Inter';
    font-style: normal;
    font-weight: 500;
    font-size: 16px;
    line-height: 24px;
    color: #FFFFFF;
    margin-top: 40px;
    cursor: pointer;
}

button:hover {
    opacity: 0.7;
    transition: opacity 0.5s ease;
}

.password-fields {
    display: flex;
    justify-content: space-between;
    padding-top: 20px;
    border-top: 1px solid #2F3E53;
    width: 446px;
    margin-top: 35px;
}

.pw-fields {
    width: 211px;
    height: 39px;
    background: #273549;
    border-radius: 6px;
    font-family: 'Inter';
    font-style: normal;
    font-weight: 500;
    font-size: 16px;
    line-height: 32px;
    text-align: center;
    color: #55F991;
    padding-top: 10px;
}

.copy-btn {
    margin-top: 10px;
    width: 211px;
}

/*Control Panel*/
.control-panel{
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    height: 230px;
    width: 446px;
}

/*Password Range Slider*/
.pw-length {
    -webkit-appearance: none;
    width: 150px;
    height: 8px;
    background: white;
    outline: none;
    opacity: .9;
    -webkit-transition: 0.2s;
    transition: opacity 0.2s;
    border-radius: 12px;   
    margin-left: 5px; 
    transition: 0.4s all ease-out;
}

.pw-length:hover {
    opacity: 1;
}

.pw-length:after {
    outline: none;
}

.pw-length::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    background: #10B981;
    border-radius: 50%;
    cursor: pointer;
    outline: none;
    transition: 0.4s all ease-out;
}

output{
    color: white;
    position: relative;
    top: 3px;
    left: 4px;
}


/*Toggle to switch on and off symbols and numbers*/
label {
    display: inline-block;
    font-size: 16px;
    color: white;
    top: 440px;
}

.Switch {
  position: absolute;
  /* Set the size of our the slider container*/
  width: 60px;
  height: 34px;
}

.Slider {
  position: absolute;
  /* Change the cursor so the user knows they can click on the element */
  cursor: pointer;
  top: 0;
  left: 10px;
  right: 0;
  bottom: 0;
  /* The border-radius could be any value since we have specified the height and width 
  but removing it would cause the container to have square corners */
  border-radius: 1rem;
  /* Default the background-color to lightgray unless the checkbox is in a checked state */
  background-color: white;
}

.Switch_Input {
  /* Hide the checkbox input from the user but keep it in the DOM */
  opacity: 0;
  width: 0;
  height: 0;
}

/* New selector for the circle pseudo-element */
.Slider::before {
  position: absolute;
  content: "";
  height: 26px;
  width: 26px;
  left: 4px;
  bottom: 4px;
  border-radius: 50%;
  background-color: #10B981;
  transition: 0.3s;
}


.Switch_Input:checked + .Slider::before {
  /* Move the circle pseudo-element from left to right and right to left when the input is checked */
  transform: translateX(16px);
  background-color: white;
}

.Switch_Input:checked + .Slider {
  /* Change the color of the slider container when it is clicked (or checked) */
  background-color: #10B981;
}

/*Tooltip*/
.tooltip .tooltiptext {
  visibility: hidden;
  width: 120px;
  background-color: #555;
  color: #fff;
  text-align: center;
  padding: 5px 0;
  border-radius: 6px;
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  margin-left: -60px;
  opacity: 0;
  transition: opacity .1s;
}

.tooltip .tooltiptext::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  margin-left: -5px;
  border-width: 5px;
  border-style: solid;
  border-color: #555 transparent transparent transparent;
}


.tooltip:active .tooltiptext {
  visibility: visible;
  opacity: 1; 
}