Material design like styles

md.css

.md-container {
  position: relative;
  width: 100%;
}

.container {
  position: relative;
  width: 100%;
  height: 3em;
  color: var(--grey-700);
}

.md-select__btn {
  position: relative;
  display: flex;
  align-items: center;
  width: 100%;
  height: max-content;
  min-height: 3em;
  transition: all 0.2s linear;
}

.md-select__btn:focus,
.md-select__btn:active {
  outline: none;
}

.md-border,
.md-select__btn::before {
  position: absolute;
  left: 0;
  width: 100%;
  pointer-events: none;
  content: "";
}

.md-outlined .md-border,
.md-outlined .md-select__btn::before {
  top: 0;
  height: 100%;
  border: 1px solid var(--grey-500);
  border-radius: 4px;
}

.md-filled .md-border,
.md-filled .md-select__btn::before {
  bottom: 0;
  height: 0;
  border-bottom: 1px solid var(--grey-500);
}

.md-round-icon-btn {
  padding: 0.7em;
  color: var(--md-focus-color);
  border-radius: 50%;
}

.md-round-icon-btn:focus,
.md-round-icon-btn:not(:disabled):hover {
  cursor: pointer;
  background-color: rgba(60, 64, 67, 0.08);
  outline: none;
}

.md-filled .md-select__btn {
  padding: 0 1em;
}

.md-label {
  position: absolute;
  top: 0.75em;
  left: 1em;
  font-weight: normal;
  pointer-events: none;
  cursor: pointer;
  transition: all 0.1s linear;
}

.md-input {
  position: relative;
  display: block;
  flex: 1;
  width: 100%;
  height: 100%;
  color: var(--grey-900);
  transition: all 0.3s linear;
}

.md-filled .md-input {
  padding: 1em 1em 0.3em;
}

.md-filled .md-select__btn,
.md-filled .md-input {
  background-color: var(--grey-100);
  border-radius: 4px 4px 0 0;
}

.md-outlined .md-input,
.md-outlined .md-select__btn {
  padding: var(--md-outlined-input-padding);
}

.md-input::placeholder {
  opacity: 0;
}

.md-input:focus:not(.invalid) {
  caret-color: var(--md-focus-color);
}

.md-input.invalid {
  caret-color: var(--dark-red);
}

.md-input.invalid ~ .md-label,
.md-select__btn.invalid .md-label {
  color: var(--dark-red) !important;
}

.md-input:focus ~ .md-label,
.md-select__btn:focus .md-label,
.md-container:focus-within .md-label {
  color: var(--md-focus-color);
}

.md-input.invalid ~ .md-border,
.md-select__btn.invalid::before {
  border-color: var(--dark-red) !important;
}

.md-input:disabled ~ .md-border,
.md-select__btn:disabled::before {
  border-color: var(--grey-300);
}

.md-input:focus:not(.invalid) ~ .md-border,
.md-container:focus-within .md-select__btn::before {
  border-color: var(--md-focus-color);
  border-width: 2px;
}

.md-filled .md-input:focus,
.md-filled.md-container:focus-within .md-select__btn {
  background-color: var(--grey-300);
}

.md-filled .md-input:hover:not(:disabled):not(:focus),
.md-filled.md-container:not(:focus-within) .md-select__btn:hover {
  background-color: var(--grey-200);
}

.md-input:hover:not(:disabled):not(:focus):not(.invalid) ~ .md-border,
.md-container:not(:focus-within) .md-select__btn:hover:not(.invalid):not(:disabled)::before {
  border-color: var(--grey-900);
}

.md-filled .md-label.filled,
.md-filled .md-input:focus ~ .md-label,
.md-filled .md-input:not(:placeholder-shown) ~ .md-label {
  top: 0.2em;
  left: 1.5em;
  font-size: 0.7em;
}

.md-outlined .md-input:focus ~ .md-label,
.md-outlined .md-input:not(:placeholder-shown) ~ .md-label,
.md-outlined .md-label.filled {
  top: -0.7em;
  padding: 0 0.5em;
  font-size: 0.7em;
  background-color: white;
}