style.css

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  border-radius: 0.25em;
}

body {
  background-color: gainsboro;
  text-align: center;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

button {
  color: white;
}

.none {
  display: none;
}

.crossed {
  text-decoration: line-through;
  text-decoration-color: gray;
}

span.crossed {
  color: gray;
}

header h2 {
  padding: 0.5em 0;
  border-bottom: 0.25em solid gray;
  border-radius: 0;
}

.card {
  width: 25em;
  min-height: 20em;
  height: auto;
  margin: 6em auto;
  padding: 2em;
  background-color: white;
  box-shadow: -3px -2px 14px 0px;
}

.card main {
  display: flex;
  flex-direction: column;
  gap: 0.5em;
  margin-top: 0.5em;
}

.card main input {
  border: 1px solid lightgray;
  padding: 0.8em;
}

.card main #addTask {
  background-color: darkcyan;
  border: none;
  padding: 0.8em;
}

.tasks {
  display: flex;
  flex-direction: column;
  gap: 0.5em;
}

.tasks .task {
  border: 1px solid lightgray;
  background-color: lavender;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5em;
}

.tasks .task span {
  text-align: left;
}

.tasks .task .actions {
  display: flex;
}

.tasks .task button {
  padding: 0.8em;
  margin: 0 0.25em;
  border: none;
}

.tasks .task button.complete {
  background-color: forestgreen;
}

.tasks .task button.remove {
  background-color: crimson;
}