* {
  margin: 0;
  padding: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  box-sizing: border-box;
}

body {
  background: #080808;
  color: #fff;
}

#header {
  width: 100%;
}

#main-header {
  width: 100%;
  height: 100vh;
  background-image: url(portfolio/images/avatar.png);
  background-repeat: no-repeat;
  background-position: 90%;
  background-size: 50%;
  z-index: 2;
}

#back {
  margin-top: 5vh;
  padding: 30px 0;
}

.container {
  padding: 10px 10%;
}

nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  z-index: 2;
}

.logo {
  width: 140px;
}

nav ul li {
  display: inline-block;
  list-style: none;
  margin: 10px 20px;
  z-index: 2;
}

nav ul li a {
  color: #fff;
  text-decoration: none;
  font-size: 18px;
  position: relative;
  z-index: 2;
}

nav ul li a::after {
  content: "";
  width: 0%;
  height: 2px;
  background: #ff8800;
  position: absolute;
  left: 0;
  bottom: -6px;
  transition: 0.25s;
  border-radius: 2px;
  z-index: 2;
}

nav ul li a:hover::after {
  width: 100%;
}

.header-text {
  margin-top: 20%;
  font-size: 30px;
  z-index: 2;
}

.header-text h1 {
  font-size: 60px;
  margin-top: 20px;
  z-index: 2;
}

.header-text h1 span {
  color: #ff8800;
  z-index: 2;
}

/* -------------- index -------------- */

.header-text-main {
  margin-top: 12.5%;
  font-size: 30px;
  z-index: 2;
}

.header-text-main h1 {
  font-size: 60px;
  margin-top: 20px;
  z-index: 2;
}

.header-text-main h1 span {
  color: #ff8800;
  z-index: 2;
}

.card-list {
  margin-top: 50px;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding: 0;
  z-index: 2;
}

.card-list li {
  background: #262626;
  padding: 40px;
  font-size: 16px;
  font-weight: 400;
  border-radius: 10px;
  transition: 0.5s;
  cursor: pointer;
  width: 50%;
  z-index: 2;
}

.card-list li a {
  text-decoration: none;
  color: #fff;
  z-index: 2;
}

.card-list li:hover {
  background: #ff8800;
  transform: translateY(-6px);
  z-index: 2;
}

.card-list li h2 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 6px;
  z-index: 2;
}

/* -------------- about -------------- */

#about {
  padding: 80px 0;
  color: #ababab;
}

.row {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
}

.about-col-1 {
  flex-basis: 35%;
  margin-bottom: 20px;
}
.about-col-1 img {
  width: 100%;
  border-radius: 15px;
}

.img-gradient-s1 {
  display: block; /* avoid inline gaps */
  mask-image: linear-gradient(
    5deg,
    rgba(0, 0, 0, 0) 0%,
    rgba(0, 0, 0, 0) 12.5%,
    rgba(0, 0, 0, 1) 60%,
    rgba(0, 0, 0, 1) 100%
  );
  mask-size: 100% 100%;
  mask-repeat: no-repeat;
  -webkit-mask-image: linear-gradient(
    5deg,
    rgba(0, 0, 0, 0) 0%,
    rgba(0, 0, 0, 0) 12.5%,
    rgba(0, 0, 0, 1) 60%,
    rgba(0, 0, 0, 1) 100%
  );
  -webkit-mask-size: 100% 100%;
  -webkit-mask-repeat: no-repeat;
  z-index: 0;
}

.about-col-2 {
  flex-basis: 60%;
}

.sub-title {
  font-size: 60px;
  font-weight: 600;
  color: #fff;
}

.tab-titles {
  display: flex;
  margin: 20px 0 40px;
}

.tab-links {
  margin-right: 50px;
  font-size: 18px;
  font-weight: 500;
  cursor: pointer;
  position: relative;
  transition: 0.25s;
}

.tab-links::after {
  content: "";
  width: 0;
  height: 2px;
  border-radius: 2px;
  background: #ff8800;
  position: absolute;
  left: 0;
  bottom: -4px;
  transition: 0.5s;
}

.tab-links:hover {
  color: #fff;
}

.tab-links.active-link::after {
  width: 125%;
}

.tab-contents ul li {
  list-style: none;
  margin: 10px 0;
}

.tab-contents ul li span {
  color: #cf9757;
  font-size: 14px;
}

.tab-contents {
  display: none;
}

.tab-contents.active-tab {
  display: block;
}

/* -------------- services -------------- */

#services {
  padding: 30px 0;
}

.services-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 40px;
  margin-top: 50px;
}

.services-list div {
  background: #262626;
  padding: 40px;
  font-size: 16px;
  font-weight: 400;
  border-radius: 10px;
  transition: 0.5s;
}

.services-list div i {
  font-size: 50px;
  margin-bottom: 30px;
}

.services-list div h2 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 15px;
}

.services-list div a {
  text-decoration: none;
  color: #ababab;
  font-size: 12px;
  margin-top: 20px;
  display: inline-block;
  font-weight: 700;
}

.services-list div:hover {
  background: #ff8800;
  transform: translateY(-10px);
}

/* -------------- portfolio -------------- */

#portfolio {
  padding: 30px 0;
}

.portfolio-card-list {
  display: grid;
  grid-template-columns: auto auto auto;
  gap: 40px;
  margin-top: 50px;
}

.portfolio-card {
  background: #262626;
  padding: 40px;
  font-size: 16px;
  font-weight: 400;
  border-radius: 10px;
  transition: 0.5s;
  text-decoration: none;
  color: #fff;
}

.portfolio-card:hover {
  background: #ff8800;
  transform: translateY(-6px);
}

.portfolio-card h2 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 6px;
}

/* -------------- contact -------------- */

#contact {
  padding: 30px 0;
}

.contact-list {
  display: inline;
  margin-top: 50px;
}

.contact-list ul li {
  list-style: none;
  margin: 10px 0;
  font-size: 18px;
}

.contact-list ul li a {
  text-decoration: none;
  color: #bbb;
  transition: 0.25s;
}

.contact-list ul li a i {
  margin-right: 12px;
}

.contact-list ul li span {
  color: #cf9757;
  font-size: 14px;
}

.contact-list ul li a:hover {
  color: #fff;
}

/* extra page css */

.portfolio-section-list {
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: 16px;
}

.portfolio-section-list li h2 {
  font-size: 22px;
}

.portfolio-section-list li {
  text-decoration: none;
  color: #fff;
  margin-top: 25px;
}

.section-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  align-items: center;
  gap: 22px;
  width: 100%;
  margin-top: 20px;
}

.section-gallery img {
  width: 100%;
  height: auto;
  max-height: 300px;
  object-fit: contain;
  display: block;
  border-radius: 8px;
  transition: 0.5s;
}

.section-gallery img:hover {
  transform: scale(1.1);
}

/* -------------- css for screens of various sizes -------------- */
@media (min-width: 2480px) {
  .card-list,
  .portfolio-card-list {
    grid-template-columns: repeat(4, 1fr);
  }

  .portfolio-section-list {
    font-size: 32px;
  }

  .portfolio-section-list li h2 {
    font-size: 36px;
  }

  .section-gallery {
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  }
  .section-gallery img {
    max-height: 600px;
  }

  .header-text h1,
  .header-text-main h1,
  .sub-title {
    font-size: 72px;
  }

  .card-list li {
    font-size: 28px;
  }

  .card-list li a h2 {
    font-size: 36px;
    font-weight: 600;
    margin-bottom: 6px;
  }

  .container {
    padding: 10px 5%;
  }

  .contact-list ul li {
    list-style: none;
    margin: 10px 0;
    font-size: 32px;
  }

  .portfolio-card {
    background: #262626;
    padding: 40px;
    font-size: 24px;
    font-weight: 400;
    border-radius: 10px;
    transition: 0.5s;
    text-decoration: none;
    color: #fff;
  }

  .portfolio-card h2 {
    font-size: 36px;
    font-weight: 600;
    margin-bottom: 6px;
  }

  .services-list div {
    background: #262626;
    padding: 40px;
    font-size: 22px;
    font-weight: 400;
    border-radius: 10px;
    transition: 0.5s;
  }

  .services-list div i {
    font-size: 50px;
    margin-bottom: 30px;
  }

  .services-list div h2 {
    font-size: 32px;
    font-weight: 600;
    margin-bottom: 15px;
  }

  .services-list div a {
    text-decoration: none;
    color: #ababab;
    font-size: 24px;
    margin-top: 20px;
    display: inline-block;
    font-weight: 700;
  }

  .tab-links {
    margin-right: 50px;
    font-size: 36px;
    font-weight: 500;
    cursor: pointer;
    position: relative;
    transition: 0.25s;
  }

  .tab-contents ul li {
    font-size: 30px;
  }

  .about-col-2 {
    font-size: 26px;
  }

  .tab-contents ul li span {
    color: #cf9757;
    font-size: 24px;
  }

  .tab-links::after {
    content: "";
    width: 0;
    height: 4px;
    border-radius: 2px;
    background: #ff8800;
    position: absolute;
    left: 0;
    bottom: -4px;
    transition: 0.5s;
  }

  nav ul li a {
    color: #fff;
    text-decoration: none;
    font-size: 32px;
    position: relative;
  }

  .header-text {
    margin-top: 20%;
    font-size: 40px;
  }
}

@media (max-width: 1200px) {
  .section-gallery {
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  }
  .section-gallery img {
    max-height: 280px;
  }

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

  .header-text h1,
  .header-text-main h1,
  .sub-title {
    font-size: 48px;
  }

  .container {
    padding: 10px 5%;
  }

  .card-list li {
    font-size: 18px;
  }

  .card-list li a h2 {
    font-size: 26px;
    font-weight: 600;
    margin-bottom: 6px;
  }
}

@media (max-width: 960px) {
  .section-gallery {
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  }
  .section-gallery img {
    max-height: 260px;
  }

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

  .header-text h1,
  .header-text-main h1,
  .sub-title {
    font-size: 48px;
  }

  .container {
    padding: 10px 5%;
  }

  #main-header {
    background-size: 75%;
    background-position-y: 100%;
    background-position-x: right;
    height: 75vh;
  }
}

@media (max-width: 768px) {
  .section-gallery {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  }
  .section-gallery img {
    max-height: 220px;
  }

  nav ul {
    flex-direction: column;
    align-items: flex-start;
  }

  nav ul li {
    margin: 10px 0;
    margin-right: 10px;
  }

  .header-text,
  .header-text-main {
    margin-top: 20%;
    font-size: 24px;
  }

  .header-text h1,
  .header-text-main h1,
  .sub-title {
    font-size: 36px;
  }

  .card-list,
  .portfolio-card-list,
  .services-list {
    grid-template-columns: 1fr;
  }

  .card-list li {
    width: 100%;
  }

  .row {
    flex-direction: column;
  }

  .about-col-1,
  .about-col-2 {
    flex-basis: 100%;
  }

  #main-header {
    padding-top: 10px;
    background-image: none;
    height: 30vh;
    margin-bottom: 40%;
  }

  .tab-titles {
    flex-direction: column;
  }

  .tab-links {
    margin-right: 0;
    margin-bottom: 10px;
    font-size: 18px;
    font-weight: 500;
    cursor: pointer;
    position: relative;
    transition: 0.25s;
  }

  .tab-links.active-link::after {
    width: 25%;
  }
}

@media (max-width: 560px) {
  .section-gallery {
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  }
  .section-gallery img {
    max-height: 200px;
  }

  #main-header {
    background-image: none;
    margin: 0;
    padding-top: 5px;
    height: 13vh;
    margin-bottom: 55%;
  }

  .about-col-1 img {
    width: 100%;
    margin-top: 12vh;
    border-radius: 15px;
  }

  .container {
    padding: 10px 3%;
  }

  .header-text,
  .header-text-main {
    font-size: 20px;
  }

  .header-text h1,
  .header-text-main h1,
  .sub-title {
    font-size: 28px;
  }

  .card-list li {
    font-size: 14px;
  }

  .card-list li a h2 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 6px;
  }

  nav {
    justify-content: center;
  }

  nav ul {
    flex-direction: column;
    align-items: flex-start;
  }

  nav ul li:not(:last-child) {
    margin-right: 20px;
  }

  nav ul li a {
    font-size: 16px;
  }

  .card-list li,
  .portfolio-card,
  .services-list div {
    padding: 20px;
  }

  .services-list div i {
    font-size: 36px;
  }

  .card-list li h2,
  .portfolio-card h2,
  .services-list div h2 {
    font-size: 20px;
  }
}

@media (max-width: 480px) {
  .section-gallery {
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
  }
  .section-gallery img {
    max-height: 180px;
  }

  #main-header {
    background-image: none;
    margin: 0;
    padding-top: 5px;
    height: 20vh;
    margin-bottom: 55%;
  }

  .about-col-1 img {
    width: 100%;
    margin-top: 12vh;
    border-radius: 15px;
  }

  .container {
    padding: 10px 3%;
  }

  .header-text,
  .header-text-main {
    font-size: 20px;
  }

  .header-text h1,
  .header-text-main h1,
  .sub-title {
    font-size: 28px;
  }

  .card-list {
    margin-top: 9.5vh;
  }

  .card-list li {
    font-size: 14px;
  }

  .card-list li a h2 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 6px;
  }

  nav {
    justify-content: center;
  }

  nav ul {
    flex-direction: column;
    align-items: flex-start;
  }

  nav ul li:not(:last-child) {
    margin-right: 20px;
  }

  nav ul li a {
    font-size: 16px;
  }

  .card-list li,
  .portfolio-card,
  .services-list div {
    padding: 20px;
  }

  .services-list div i {
    font-size: 36px;
  }

  .card-list li h2,
  .portfolio-card h2,
  .services-list div h2 {
    font-size: 20px;
  }

  .about-col-2 {
    font-size: 14px;
  }
}

@media (max-width: 390px) {
  .section-gallery {
    grid-template-columns: repeat(auto-fill, minmax(90px, 1fr));
  }
  .section-gallery img {
    max-height: 160px;
  }

  #main-header {
    background-image: none;
    margin: 0;
    padding-top: 5px;
    height: 14vh;
    margin-bottom: 75%;
  }

  .card-list {
    margin-top: 6.5vh;
  }

  .about-col-1 img {
    width: 100%;
    margin-top: 14vh;
    border-radius: 15px;
  }

  .container {
    padding: 10px 3%;
  }

  .header-text,
  .header-text-main {
    font-size: 20px;
  }

  .header-text h1,
  .header-text-main h1,
  .sub-title {
    font-size: 28px;
  }

  nav {
    justify-content: center;
  }

  nav ul {
    flex-direction: column;
    align-items: flex-start;
  }

  nav ul li:not(:last-child) {
    margin-right: 12px;
  }

  nav ul li a {
    font-size: 14px;
  }

  .card-list li,
  .portfolio-card,
  .services-list div {
    padding: 20px;
  }

  .services-list div i {
    font-size: 36px;
  }

  .card-list li a h2,
  .portfolio-card h2,
  .services-list div h2 {
    font-size: 20px;
  }

  .about-col-2 {
    font-size: 12px;
  }

  .card-list li {
    font-size: 12px;
  }

  .card-list li a h2 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 6px;
  }
}

@media (max-width: 320px) {
  .section-gallery {
    grid-template-columns: repeat(auto-fill, minmax(90px, 1fr));
  }
  .section-gallery img {
    max-height: 160px;
  }

  #main-header {
    background-image: none;
    margin: 0;
    padding-top: 5px;
    height: 19vh;
    margin-bottom: 70%;
  }

  .about-col-1 img {
    width: 100%;
    margin-top: 14vh;
    border-radius: 15px;
  }

  .container {
    padding: 10px 3%;
  }

  .header-text,
  .header-text-main {
    font-size: 20px;
  }

  .header-text h1,
  .header-text-main h1,
  .sub-title {
    font-size: 28px;
  }

  nav {
    justify-content: center;
  }

  nav ul {
    flex-direction: column;
    align-items: flex-start;
  }

  nav ul li:not(:last-child) {
    margin-right: 12px;
  }

  nav ul li a {
    font-size: 14px;
  }

  .card-list li,
  .portfolio-card,
  .services-list div {
    padding: 20px;
  }

  .services-list div i {
    font-size: 36px;
  }

  .card-list li a h2,
  .portfolio-card h2,
  .services-list div h2 {
    font-size: 20px;
  }

  .about-col-2 {
    font-size: 12px;
  }

  .card-list li {
    font-size: 12px;
  }

  .card-list li a h2 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 6px;
  }
}