/* Font sizes (px)
10 / 12 / 14 / 16 / 18 / 20 / 24 / 30 / 36 / 44 / 52 / 62 / 74 / 86 / 98

- Spacing system (px)
2 / 4 / 8 / 12 / 16 / 24 / 32 / 48 / 64 / 80 / 96 / 128
*/

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

html {
  /* FONT-SIZE = 10px */
  font-size: 62.5%;
  font-family: "Roboto Flex", sans-serif;
  overflow-x: hidden;
  scroll-behavior: smooth;
}

body {
  overflow-x: hidden;
  position: relative;
}

/*********************************/
/************ GENERAL  ***********/
/*******************************/

.headlines {
  letter-spacing: 1.5px;
  font-family: "DM Serif Text", serif;
  color: #010f0a;
}

/*********************************/
/************ HEADER  ***********/
/*******************************/

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 3.2rem 3.2rem 3.2rem 1.6rem;
  transition: all 0.3s;
  background-color: #6bbea4;
  position: relative;
  z-index: 99;
}

.logo {
  width: 9.6rem;
  filter: brightness(0);
}

.nav-list {
  display: none;
  transform: translateX(100%);
  transition: all 0.5s;
}

.hide-nav .nav-list {
  position: absolute;
  top: 0;
  left: 0;
  background-color: #229d77;
  width: 100%;
  height: 100vh;
  transform: translateX(0);

  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-evenly;
  font-size: 2.4rem;
  list-style: none;

  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

.nav-link:link,
.nav-link:visited {
  color: #032c1f;
  text-decoration: none;
  font-weight: 500;
  transition: all 0.3s;
}

.nav-link:hover,
.nav-link:active {
  transition: all 0.3s;
  color: #010f0a;
  border-bottom: 1px solid #010f0a;
  padding-bottom: 2px;
}

.login:link,
.login:visited,
.Sign-Up:link,
.Sign-Up:visited {
  background-color: #054934;
  color: #b5ded2;
  padding: 1.2rem 2.4rem;
  transition: all 0.3s;
}

.login:hover,
.login:active,
.Sign-Up:hover,
.Sign-Up:active {
  background-color: #032c1f;
  border: none;
  box-shadow: 5px 5px 0px rgba(3, 44, 31, 0.3);
}

.close-icon {
  display: none;
}

.hide-nav .close-icon {
  display: block;
  color: #b5ded2;
}

.hide-nav .menu-icon {
  display: none;
}

.close-open-icon {
  font-size: 4.8rem;
  color: #b5ded2;
}

.menu-icon:hover,
.close-icon:hover {
  cursor: pointer;
}

/* STICKY NAVIGATION */
.sticky .header {
  position: fixed;
  top: 0;
  height: 7rem;
  padding-top: 0;
  padding-bottom: 0;
  width: 100%;
  box-shadow: 0 1rem 3.2rem rgba(0, 0, 0, 0.05);
}

.sticky .hero-section {
  margin-top: 13.8rem;
}

/* REVEALING ELEMENTS ON SCROLL */

.reveal-sections {
  opacity: 0;
  transform: translateX(8rem);
}

/*********************************/
/************ HERO SECTION  ***********/
/*******************************/

.hero-section {
  padding: 0 2.8rem 3.2rem 2.8rem;
  background-color: #6bbea4;
}

.Hero-text-container {
  margin-bottom: 6.4rem;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 3.2rem;
}

.headline {
  font-size: 4.8rem;
}

.headline span {
  color: #032c1f;
}

.hero-subtext {
  font-size: 2rem;
  color: #021d15;
  font-weight: 500;
  line-height: 1.7;
}

.cta-link:link,
.cta-link:visited {
  color: #b5ded2;
  text-decoration: none;
  display: inline-block;
  font-size: 1.8rem;
  background-color: #032c1f;
  padding: 1.2rem 2.4rem;
  width: fit-content;
  margin: 0 auto;
  transition: all 0.3s;
}

.cta-link:hover,
.cta-link:active {
  box-shadow: 5px 5px 0px rgba(3, 44, 31, 0.3);
}

.hero-img {
  width: 100%;
}

/*********************************/
/****** FEATURES SECTION  *******/
/*******************************/

.feature-section {
  padding: 0 2.8rem;
  margin: 9.6rem 0;
}

.feature-headline {
  font-size: 3.2rem;
  margin-bottom: 3.2rem;
}

.grid-container {
  display: grid;
  grid-template-columns: repeat(1, 1fr);
  justify-content: center;
  gap: 2.4rem;
}

.features-grid {
  background-color: #cee9e1;
  padding: 3.2rem 2.4rem;
}

.feature-icon {
  margin-bottom: 2.4rem;
  font-size: 2.4rem;
  color: #cee9e1;
  background-color: #021d15;
  padding: 1.2rem 1.2rem;
  border-radius: 100%;
}

.features-subtext {
  font-size: 2.4rem;
  margin-bottom: 1.6rem;
  font-weight: 600;
  color: #021d15;
}

.features-minitext {
  font-size: 1.6rem;
  line-height: 1.7;
  color: #054934;
}

/*********************************/
/****** ABOUT US SECTION  *******/
/*******************************/

.about-lecturer__section {
  margin: 9.6rem 0;
  display: grid;
  grid-template-columns: repeat(1, 1fr);
  gap: 6.4rem;
}

.about-section {
  padding: 9.6rem 2.8rem;
  text-align: center;
  background-image: linear-gradient(
      rgba(34, 157, 118, 0.4),
      rgba(34, 157, 118, 0.4)
    ),
    url(../images/about.jpg);
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

.about-headline {
  font-size: 3.2rem;
  margin-bottom: 3.2rem;
}

.about-subtext {
  color: #021d15;
  font-weight: 500;
  font-size: 2.4rem;
  line-height: 1.5;
}

/*********************************/
/*** INSTRUCTOR HIGHLIGHT SECTION ***/
/*******************************/

.lecturer-highlight {
  padding: 0 2.8rem;
}

.lecturer-headline {
  font-size: 3.6rem;
  margin-bottom: 2.4rem;
}

.lecturer-subtext {
  font-size: 1.8rem;
  margin-bottom: 3.2rem;
  line-height: 1.5;
  color: #021d15;
}

.lecturers-img {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.6rem;
}

.lecturers-img img {
  width: 100%;
}

/*********************************/
/****** TESTIMONIAL SECTION  *******/
/*******************************/

.testimonial-section {
  padding: 4.8rem 2.8rem;
  margin: 9.6rem 0;
  text-align: center;
  background-color: #cee9e1;
}

.testimonial-headline {
  font-size: 3.2rem;
  margin-bottom: 4.8rem;
}

.testimonial-container {
  display: flex;
  gap: 2.4rem;
}

.testimonial-img {
  width: 100px;
  height: 100px;
  border-radius: 100%;
  margin-bottom: 2.4rem;
}

.testimonial-author {
  font-size: 2rem;
  margin-bottom: 1.2rem;
}

.testimonial-message {
  font-size: 1.4rem;
  line-height: 1.6;
}

/*********************************/
/****** FAQ SECTION  *******/
/*******************************/

.faq-section {
  padding: 4.8rem 2.8rem;
  margin: 9.6rem 0;
}

.faq-title {
  text-align: center;
  font-size: 3.2rem;
  margin-bottom: 4.8rem;
}

.faq {
  display: grid;
  grid-template-columns: (1fr);
  padding: 0 2.4rem;
  row-gap: 4.8rem;
  column-gap: 4.8rem;
}

.faq-item {
  max-width: 600px;
  border-bottom: 1px solid #021d15;
}

.faq-question {
  font-size: 1.8rem;
  background: none;
  border: none;
  width: 100%;
  display: flex;
  justify-content: space-between;
  cursor: pointer;
  color: #032c1f;
  font-weight: 600;
  margin-bottom: 1.4rem;
  line-height: 1.5;
}

.faq-question.active .icon-minus {
  display: block;
}

.faq-question.active .icon-plus {
  display: none;
}

.icon-plus,
.icon-minus {
  font-size: 2.4rem;
  color: #229d77;
  content: "+";
}

.icon-minus {
  display: none;
}

.faq-answer {
  padding: 10px;
  font-size: 1.6rem;
  color: #021d15;
  display: none;
  line-height: 1.5;
}

.faq-answer.active {
  display: block;
}

/*********************************/
/****** STATS SECTION  *******/
/*******************************/

.stats-section {
  padding: 4.8rem 2.8rem;
  margin: 9.6rem 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  column-gap: 4.8rem;
  row-gap: 4.8rem;
}

.stats {
  font-size: 2rem;
}

.stats-1 {
  border-right: 1px solid #021d15;
}

.stats-3 {
  border-right: 1px solid #021d15;
}

.stats strong {
  font-size: 4.8rem;
}

/*********************************/
/****** FOOTER SECTION  *******/
/*******************************/
.footer {
  background-color: #6bbea4;
  padding: 4.2rem 2.8rem;
}

.footer-container {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  column-gap: 3.2rem;
  row-gap: 3.2rem;
  margin-bottom: 3.2rem;
}

.social-icons {
  display: flex;
  gap: 2.4rem;
  align-items: center;
}

.footer-icon,
.account,
.contact {
  font-size: 2.4rem;
  color: #032c1f;
}

.sitemap,
.contact-section {
  display: flex;
  flex-direction: column;
  gap: 1.4rem;
  justify-content: center;
}

.sitemap ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
  font-size: 1.6rem;
}

.acct:link,
.acct:visited,
.address a:link,
.address a:visited {
  text-decoration: none;
  transition: all 0.3s;
  color: #054934;
}

.acct:hover,
.acct:active,
.address a:hover,
.address a:active {
  color: #021d15;
}

.address {
  display: flex;
  gap: 1.2rem;
  flex-direction: column;
  font-size: 1.4rem;
}

.address-no {
  line-height: 1.5;
}

.copyright,
.allrightreserved {
  padding-top: 2.4rem;
  font-size: 1.4rem;
  text-align: center;
}

/*********************************/
/****** MAX-WIDTH : 600px *******/
/*******************************/

@media (max-width: 38em) {
  html {
    font-size: 50%;
  }

  .testimonial-container {
    flex-direction: column;
    gap: 4.8rem;
  }

  .stats-section {
    grid-template-columns: repeat(1, 1fr);
    column-gap: 4.8rem;
    row-gap: 6.4rem;
  }

  .stats {
    border: none;
  }

  .footer-container {
    grid-template-columns: repeat(1, 1fr);
    column-gap: 3.2rem;
    row-gap: 4.8rem;
  }
}

/*********************************/
/****** MAX-WIDTH : 400px *******/
/*******************************/

@media (max-width: 25em) {
  html {
    font-size: 37.5%;
  }
}

/*********************************/
/****** MIN-WIDTH : 650px *******/
/*******************************/

@media (min-width: 41em) {
  html {
    font-size: 56.25%;
  }

  .grid-container {
    grid-template-columns: repeat(2, 1fr);
  }
}

/*********************************/
/****** MIN-WIDTH : 800px *******/
/*******************************/

@media (min-width: 50em) {
  .lecturer-highlight {
    display: grid;
    grid-template-columns: 1.3fr 1fr;
    gap: 3.2rem;
  }
}

/*********************************/
/****** MIN-WIDTH : 900px *******/
/*******************************/

@media (min-width: 56em) {
  html {
    font-size: 50%;
  }

  .nav-list {
    list-style: none;
    display: flex;
    justify-content: space-evenly;
    gap: 5.2rem;
    font-size: 1.8rem;

    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateX(0);
  }

  .close-open-icon {
    display: none;
  }

  .about-lecturer__section {
    margin: 0;
    padding: 0 2.8rem;
    grid-template-columns: repeat(2, 1fr);
    gap: 2.4rem;
  }

  .lecturer-highlight {
    display: block;
  }

  html {
    font-size: 8px;
  }

  .hero-section {
    padding: 8rem 0;
  }
  .img-text--container {
    display: flex;
    margin: 0 auto;
    gap: 4.8rem;
    width: 90%;
  }

  .headline {
    font-size: 3.2rem;
  }

  .hero-subtext {
    font-size: 1.8rem;
  }

  .Hero-text-container {
    margin-bottom: 0;
    text-align: left;
    justify-content: center;
  }

  .hero-img-container {
    width: 100%;
  }

  .cta-link:link,
  .cta-link:visited {
    margin: 0;
  }

  .about-section {
    padding: 9.6rem 2.8rem;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
  }

  .grid-container {
    grid-template-columns: repeat(4, 1fr);
  }

  .faq {
    grid-template-columns: repeat(2, 1fr);
  }

  .faq-item {
    border-bottom: none;
  }

  .stats-section {
    grid-template-columns: repeat(4, 1fr);
  }

  .stats-2 {
    border-right: 1px solid #021d15;
  }

  .footer-container {
    grid-template-columns: repeat(4, 1fr);
    margin-bottom: 3.2rem;
  }
}

/*********************************/
/****** MIN-WIDTH : 1200px *******/
/*******************************/

@media (min-width: 75em) {
  html {
    font-size: 62.5%;
  }

  .headline {
    font-size: 5.2rem;
  }

  .hero-subtext {
    font-size: 2.4rem;
  }
}