advanced-css/Trillo/starter/sass/_components.scss

// Logo
.logo {
  height: 3.25rem;
  margin-left: 2rem;
}

// Search
.search {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 40%;

  &__input {
    font-family: inherit;
    font-size: inherit;
    color: inherit;
    border: none;
    background-color: var(--color-grey-light-2);

    padding: 0.7rem 2rem;
    border-radius: 100px;
    width: 90%;

    transition: all 0.2s;

    margin-right: -3.25rem;

    &:focus {
      outline: none;
      width: 100%;
      background-color: var(--color-grey-light-3);
    }

    &::placeholder,
    &::-webkit-input-placeholder {
      font-weight: 100;
      color: var(--color-grey-light-4);
    }
  }

  &__input:focus + &__button {
    background-color: var(--color-grey-light-3);
  }

  &__button {
    border: none;
    background-color: var(--color-grey-light-2);

    &:focus {
      outline: none;
    }

    &:active {
      transform: translateY(2px);
    }
  }

  &__icon {
    height: 2rem;
    width: 2rem;
    fill: var(--color-grey-dark-3);
  }
}

// User nav
.user-nav {
  display: flex;
  align-items: center;
  align-self: stretch; //NOTE: make it cover the entire height

  & > * {
    height: 100%;
    padding: 0 2rem;
    cursor: pointer;
    display: flex;
    align-items: center;
  }

  & > *:hover {
    background-color: var(--color-grey-light-2);
  }

  &__icon-box {
    position: relative;
  }

  &__icon {
    height: 2.25rem;
    width: 2.25rem;

    fill: var(--color-grey-dark-3);
  }

  &__notification {
    font-size: 0.8rem;
    height: 1.75rem;
    width: 1.75rem;
    border-radius: 50%;
    background-color: var(--color-primary);
    color: white;
    position: absolute;
    top: 1.5rem;
    right: 1.1rem;

    display: flex;
    justify-content: center;
    align-items: center;
  }

  &__user-photo {
    height: 3.75rem;
    border-radius: 50%;
    margin-right: 1rem;
  }
}

// Side navigation
.side-nav {
  font-size: 1.4rem;
  list-style: none;
  margin-top: 3.5rem;

  &__item {
    position: relative;

    &:not(:last-child) {
      margin-bottom: 0.5rem;
    }
  }

  &__item::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 3px;
    background-color: var(--color-primary);
    transform: scaleY(0);

    transform-origin: center; //NOTE: cool
    transition:
      transform 0.2s,
      width 0.4s cubic-bezier(1, 0, 0, 1) 0.2s,
      //NOTE: duration timing delay
      background-color 0.1s;
  }

  &__item:hover::before,
  &__item--active::before {
    transform: scaleY(1);
    width: 100%;
  }

  &__item:active::before {
    background-color: var(--color-primary-light);
  }

  &__link:link,
  &__link:visited {
    color: var(--color-grey-light-1);
    text-decoration: none;
    text-transform: uppercase;
    display: flex;
    align-items: center;
    padding: 1.5rem 3rem;

    position: relative;
    z-index: 10;
  }

  &__icon {
    width: 1.75rem;
    height: 1.75rem;
    margin-right: 2rem;
    fill: currentColor; //NOTE: color of current or parent element
  }
}

// Legal
.legal {
  font-size: 1.2rem;
  color: var(--color-grey-light-4);
  text-align: center;
  padding: 2.5rem;
}

// Gallery
.gallery {
  display: flex;

  &__photo {
    width: 100%;
    display: block;
  }
}

// Overview
.overview {
  display: flex;
  align-items: center;
  border-bottom: 1px solid var(--color-grey-light-2);

  &__heading {
    font-size: 2.25rem;
    font-weight: 300;
    text-transform: uppercase;
    letter-spacing: 1px;

    padding: 1.5rem 3rem;
  }

  &__stars {
    margin-right: auto; // NOTE: to imitate flex: 1 effect but with a small final box, instead of one that extends all the space
    display: flex; // NOTE: because svg behave like inline so is either this or set line-height: 0 and font-size: 0;
  }

  &__icon-star,
  &__icon-location {
    width: 1.75rem;
    height: 1.75rem;
    fill: var(--color-primary);
  }

  &__location {
    font-size: 1.2rem;
    display: flex;
    vertical-align: center;
  }

  &__icon-location {
    margin-right: 0.5rem;
  }

  &__rating {
    background-color: var(--color-primary);
    color: white;
    margin-left: 3rem;
    padding: 0 2.25rem;
    align-self: stretch;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
  }

  &__rating-average {
    font-size: 2.25rem;
    font-weight: 300;
    margin-bottom: -3px;
  }

  &__rating-count {
    font-weight: 0.8rem;
    text-transform: uppercase;
  }
}

// btn
.btn-inline {
  border: none;
  color: var(--color-primary);
  font-size: inherit; // NOTE: to make it more reusable
  border-bottom: 1px solid currentColor;
  padding-bottom: 2px;
  display: inline-block;
  background-color: transparent;
  cursor: pointer;
  transition: all 0.2s;

  &:hover {
    color: var(--color-grey-dark-1);
  }

  &:focus {
    outline: none;
    animation: pulsate 1s infinite;
  }
}

@keyframes pulsate {
  0% {
    transform: scale(1); // NOTE: needs an initial value in order to animate
    box-shadow: none;
  }
  50% {
    transform: scale(1.05);
    box-shadow: 0 1rem 4rem rgba(0, 0, 0, 0.25);
  }
  100% {
    transform: scale(1);
    box-shadow: none;
  }
}