style.css

* {
  margin: 0px;
  padding: 0px;
  box-sizing: border-box;
  font-family: "Montserrat", sans-serif;
  color: white;
}
body {
  height: 100%;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  background-image: linear-gradient(to top, #209cff 0%, #68e0cf 100%);
}
button {
  border: 0;
  outline: 0;
}
.container {
  width: 400px;
  height: 600px;
  margin: 40px 0px;
  padding: 10px 25px;
  background: #0a0e31;
  border-radius: 10px;
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.45), 0 4px 8px rgba(0, 0, 0, 0.35),
    0 8px 12px rgba(0, 0, 0, 0.15);
  /* display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center; */
}
.container h2 {
  font-size: 1.75rem;
  color: white;
  margin: 10px 0 30px 0;
}
.result {
  width: 100%;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 8px;
  text-align: center;
  line-height: 65px;
}

.length-slider {
  margin-top: 15px;
  text-transform: uppercase;
  font-size: 12px;
  font-weight: bold;
  opacity: 0.6;
}
.range-slider {
  position: relative;
  width: 100%;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 8px;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 65px;
}
.range-slider::before {
  content: attr(data-min);
  left: 10px;
}
.range-slider::after {
  content: attr(data-max);
  right: 10px;
}
.range-slider::before,
.range-slider::after {
  position: absolute;
  color: #fff;
  font-size: 0.9rem;
  font-weight: bold;
}

#slider {
  -webkit-appearance: none;
  position: relative;
  width: 80%;
  cursor: pointer;
  background: rgba(255, 255, 255, 0.314);
  height: 4px;
  outline: none;
  border-radius: 8px;
  padding: 0;
  margin: 0;
  cursor: pointer;
}
#slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: white;
  cursor: pointer;
  transition: all 0.15s ease-in-out;
}

#slider::-webkit-slider-thumb:hover {
  background: #d4d4d4;
  transform: scale(1.2);
}
#slider::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border: 0;
  border-radius: 50%;
  background: white;
  cursor: pointer;
  transition: background 0.15s ease-in-out;
}
#slider::-moz-range-thumb:hover {
  background: #d4d4d4;
}
.settings-title {
  margin-top: 15px;
  text-transform: uppercase;
  font-size: 12px;
  font-weight: bold;
  opacity: 0.6;
}

.settings {
  position: relative;
  height: auto;
  widows: 100%;
  display: flex;
  flex-direction: column;
}

.settings .setting {
  position: relative;
  width: 100%;
  height: calc(65px - 10px);
  background: rgba(214, 135, 135, 0.08);
  border-radius: 8px;
  display: flex;
  align-items: center;
  padding: 10px 25px;
  color: #fff;
  margin-bottom: 8px;
}
.settings .setting input {
  opacity: 0;
  position: absolute;
}
.settings .setting input + label {
  user-select: none;
}
.settings .setting input + label::before,
.settings .setting input + label::after {
  content: "";
  position: absolute;
  transition: 150ms cubic-bezier(0.24, 0, 0.5, 1);
  transform: translateY(-50%);
  top: 50%;
  right: 10px;
  cursor: pointer;
}
.settings .setting input + label::before {
  height: 30px;
  width: 50px;
  border-radius: 30px;
  background: rgba(214, 214, 214, 0.434);
}
.settings .setting input + label::after {
  height: 24px;
  width: 24px;
  border-radius: 60px;
  right: 32px;
  background: #fff;
}
.settings .setting input:checked + label:before {
  background: #5d68e2;
  transition: all 150ms cubic-bezier(0, 0, 0, 0.1);
}
.settings .setting input:checked + label:after {
  right: 14px;
}
.settings .setting input:focus + label:before {
  box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.75);
}

.btn-generate {
  user-select: none;
  position: relative;
  width: 100%;
  height: 50px;
  margin: 10px 0;
  border-radius: 8px;
  border: none;
  background-image: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  letter-spacing: 1px;
  font-weight: bold;
  cursor: pointer;
  text-transform: uppercase;
  transition: all 150ms ease;
}
.btn-generate:active {
  transform: translateY(-3%);
  box-shadow: 0 4px 8px rgba(255, 255, 255, 0.08);
}