html {
  font-family: 'Ubuntu', sans-serif;
  display: block;
  box-sizing: border-box;
  -webkit-font-smoothing: antialiased;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  -ms-box-sizing: border-box;
  box-sizing: border-box;
}

body {
  color: #000;
  margin: 0 auto;
  padding: 0;
  width: 100%;
}

/*********** header ***********/
header > h1 {
  display: inline-block;
  font-size: 2.8em;
  padding-left: 1.2rem;
}

header > span {
  font-size: 0.9em;
  color: #797979;
  margin-left: 1rem;
  text-align: center;
}

/*********** navigation bar ***********/
.flex-nav {
  display: flex;
  flex-direction: row;
  margin: 0;
  justify-content: flex-end;
  padding-right: 5%;
}

.flex-nav li {
  padding: 1% 10px 2% 10px;
  list-style: none;
}

.flex-nav > li > a {
  text-decoration: none;
  color: black;
}

.active-page {
  color: #5fbea6 !important;
  font-weight: bold;
}

.mail-link {
  color: black;
}

/*********** main  ***********/
main > h1 {
  margin: 0;
  padding: 1.4rem;
}

main > p {
  margin: 0;
  padding: 0 7rem 1.3rem 7rem;
}

main picture img {
  display: block;
  margin: 0 auto;
}

.portfolio-text {
  padding-top: 0.8rem;
}

.projects {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-evenly;
}

.projects div {
  margin-bottom: 1rem;
  text-align: center;
}

/*********** portfolio hover effect  ***********/

.container {
  position: relative;
}

.container:hover .overlay {
  opacity: 0.5;
  transform: scale(1);
}

.text {
  color: white;
  font-size: 20px;
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
  text-align: center;
}

.overlay {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  height: 100%;
  width: 100%;
  opacity: 0;
  transition: all 0.2s ease-in-out;
  background-color: black;
}

/*********** responsiveness  ***********/
@media only screen and (max-width: 350px) {
  html {
    font-size: 0.8em;
  }
  header > h1 {
    font-size: 2.2em;
  }

  header > span {
    display: none;
  }

  main > h1 {
    font-size: 0.8em;
  }

  main > p {
    margin: 0;
    padding: 0 3rem 1.3rem 3rem;
  }
}

@media only screen and (min-width: 351px) and (max-width: 600px) {
  html {
    font-size: 0.9em;
  }

  header > h1 {
    font-size: 2.6em;
  }

  header > span {
    display: none;
  }

  main > h1 {
    font-size: 1.5em;
  }

  main > p {
    margin: 0;
    padding: 0 3rem 1.3rem 3rem;
  }
}

@media only screen and (min-width: 601px) and (max-width: 1023px) {
  main > p {
    margin: 0;
    padding: 0 5rem 1.3rem 5rem;
  }
}

@media only screen and (min-width: 1024px) {
  html {
    font-size: 1.1em;
  }
  header > h1 {
    font-size: 2.8em;
  }

  main > h1 {
    font-size: 1.7em;
  }

  main > p {
    margin: 0;
    padding: 0 9rem 1.3rem 9rem;
  }
}