frontend/src/styles/_base.scss

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

:root {
  --color-text: #333;
  --color-background: #fff;
  --color-primary: #3f51b5;
  --color-primary-text: #fff;
  --drop-shadow: drop-shadow(0 10px 10px rgb(0, 0, 0, 0.2));
  --dropdown-arrow: url("data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%2225%22%20height%3D%2210%22%3E%3Cpath%20fill%3D%22%23333%22%20fill-opacity%3D%221%22%20stroke%3D%22none%22%20d%3D%22M0%2C0%20L0%2C0%20L1%2C0%20L1%2C6%20L7%2C6%20L7%2C7%20L0%2C7%20z%22%20transform%3D%22rotate(-45%205%200)%22%20%2F%3E%3C%2Fsvg%3E");
}

html, body {
  height: 100%;
}

body {
  font-family: "Noto Sans", sans-serif;
  font-size: 13px;
  color: var(--color-text);
}

a {
  color: var(--color-primary);
}

ul {
  list-style: inside;
}

#app {
  display: flex;
  min-height: 100%;
  flex-direction: column;

  // Only select immediate child as the datepicker contains a <header> as well
  > header {
    display: flex;
    padding: 20px;
    white-space: nowrap;
    overflow-x: auto;
    color: var(--color-primary-text);
    background: var(--color-primary);

    nav {
      display: flex;
      flex: 1;

      &:not(:first-child) {
        margin-left: 20px;
      }

      &.nav-shrink {
        flex: 0 1 auto;
      }

      .nav-item:not(:first-child) {
        margin-left: 20px;
      }

      .feather {
        font-size: 20px;
        margin-right: 10px;
        position: relative;
        top: -2px;
        vertical-align: middle;
      }

      .button-icon .feather {
        margin: 0;
      }
    }
  }

  main {
    flex: 1;
    position: relative;
  }
}

.button,
.vdp-datepicker input {
  cursor: pointer;
  color: var(--color-text);
  background: var(--color-background);
  border: 0;
  border-radius: 18px;
  padding: 8px 16px;
}

.button-outline {
  border: 1px solid var(--color-background);
  color: var(--color-primary-text);
  background: transparent;
}

.button-flat {
  color: var(--color-primary-text);
  background: transparent;
}

.button-icon {
  padding: 8px 0;
}

.dropdown {
  display: inline-block;
}

.dropdown-button,
.vdp-datepicker input {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  background-image: var(--dropdown-arrow);
  background-repeat: no-repeat;
  background-position-x: right;
  background-position-y: center;
  padding-right: 30px;
}

.dropdown-body {
  display: none;
  position: absolute;
  margin-top: 12px;
  padding: 8px 0;
  border-radius: 3px;
  color: var(--color-text);
  background: var(--color-background);
  filter: var(--drop-shadow);
  z-index: 2000;

  label {
    cursor: pointer;
    display: block;
    padding: 8px 15px;

    &:hover {
      background: rgba(0, 0, 0, 0.1);
    }

    input[type=checkbox] {
      position: relative;
      top: 2px;
    }
  }
}

.dropdown-body::before,
.vdp-datepicker .vdp-datepicker__calendar::before {
  content: "";
  border-left: 10px solid transparent;
  border-right: 10px solid transparent;
  border-top: 10px solid transparent;
  border-bottom: 10px solid var(--color-background);
  position: absolute;
  top: -20px;
  left: 20px;
}

.dropdown:focus-within .dropdown-body {
  display: block;
}