*,
::before,
::after {
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

:root {
  --color-one: #009688;
  --color-two: #ddd;
  --main-padding: 1rem;
}

body {
  margin: 0;
  font-family: 'Montserrat', sans-serif;
  background-color: #eee;
}

.container {
  margin: 2rem;
  padding-top: var(--main-padding);
  padding-bottom: var(--main-padding);
  background-color: white;
}

h3 {
  position: relative;
  width: -webkit-fit-content;
  width: -moz-fit-content;
  width: fit-content;
  margin-left: -0.5rem;
  padding: 0.5rem 1rem;
  background-color: var(--color-one);
  color: white;
}

h3::before {
  content: '';
  position: absolute;
  left: 3px;
  bottom: calc(0px - 0.3rem);
  -webkit-transform: rotateZ(-45deg);
  -ms-transform: rotate(-45deg);
  transform: rotateZ(-45deg);
  border: 5px solid;
  border-color: transparent transparent transparent #0a7369;
}

input[type='checkbox'],
label {
  cursor: pointer;
}

input[type='checkbox'] {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  position: relative;
  top: 6px;
  width: 1rem;
  height: 1rem;
  border: 1px solid var(--color-two);
  border-radius: 5px;
  background-color: white;
}

input[type='checkbox']:checked + label {
  text-decoration: line-through;
}

input[type='checkbox']:checked::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 75%;
  height: 75%;
  border: 1px solid var(--color-two);
  border-radius: 2px;
  background-color: var(--color-one);
  -webkit-transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}

.article {
  margin: 1rem;
  padding: 1rem;
  background-color: #f9f9f9;
}

/* personal footer */

footer {
  margin-top: 2rem;
  padding-top: 1rem;
  padding-bottom: 1rem;
  line-height: 1.5;
  text-align: center;
}

.platform {
  font-weight: 500;
  color: #2eca7f;
}

.coder {
  font-weight: 500;
  color: #cf2937;
}

a {
  text-decoration: none;
}