html {
  background: #f4f5f6;
  font-family: Rewir;
  color: #121212;
  scroll-behavior: smooth;
}
body {
  height: 100%;
  padding: 0;
  display: grid;
  grid-template-columns: 2fr 6fr 2fr;
  margin: 120px;
  gap: 30px;
}

#col-nav    { grid-column: 1; }
#col-main   { grid-column: 2; }
#col-contact { grid-column: 3; }

a {
  color: #b83d00;
  text-align: left;
  width: 171px;
}
a:link {
  text-decoration: none;
}
a:visited {
  text-decoration: none;
}
a:hover {
  text-decoration: none;
}
a:active {
  color: #f4f5f6;
}
/*menu*/
nav {
  display: inline-flex;
  flex-direction: column;
  margin: 0;
  width: 350.28px;
  position: fixed;
}
#menu {
  display: flex;
  width: 224px;
  flex-direction: column;
  align-items: flex-start;
  gap: 30px;
}
#menu-links {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 30px;
}
.menu_item {
  display: block;
  font-weight: normal;
  font-size: 16px;
}
.menu_item--mobile {
  display: none;
}
#nav-icon4 {
  display: none;
  width: 35px;
  height: 35px;
  position: relative;
  cursor: pointer;
  -webkit-transform: rotate(0deg);
  -moz-transform: rotate(0deg);
  -o-transform: rotate(0deg);
  transform: rotate(0deg);
  -webkit-transition: .5s ease-in-out;
  -moz-transition: .5s ease-in-out;
  -o-transition: .5s ease-in-out;
  transition: .5s ease-in-out;
}
#nav-icon4 span {
  display: block;
  position: absolute;
  height: 5px;
  width: 100%;
  background: #121212;
  border-radius: 5px;
  opacity: 1;
  left: 0;
  -webkit-transform: rotate(0deg);
  -moz-transform: rotate(0deg);
  -o-transform: rotate(0deg);
  transform: rotate(0deg);
  -webkit-transform-origin: center center;
  -moz-transform-origin: center center;
  -o-transform-origin: center center;
  transform-origin: center center;
  -webkit-transition: top .5s ease-in-out, transform .5s ease-in-out, opacity .5s ease-in-out, width .5s ease-in-out;
  -moz-transition: top .5s ease-in-out, transform .5s ease-in-out, opacity .5s ease-in-out, width .5s ease-in-out;
  -o-transition: top .5s ease-in-out, transform .5s ease-in-out, opacity .5s ease-in-out, width .5s ease-in-out;
  transition: top .5s ease-in-out, transform .5s ease-in-out, opacity .5s ease-in-out, width .5s ease-in-out;
}
#nav-icon4 span:nth-child(1) { top: 0px; }
#nav-icon4 span:nth-child(2) { top: 15px; }
#nav-icon4 span:nth-child(3) { top: 30px; }

#nav-icon4.open span:nth-child(1) {
  top: 15px;
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
}
#nav-icon4.open span:nth-child(2) {
  width: 0%;
  opacity: 0;
}
#nav-icon4.open span:nth-child(3) {
  top: 15px;
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  transform: rotate(-45deg);
}

/*hero*/
#description {
  font-size: 17px;
  font-style: normal;
  font-weight: 300;
  line-height: normal;
}

.titles {
  position: absolute;
  left: 10%;
}

h1 {
  margin: 0;
  padding: 0;
  font-size: 22px;
  font-style: normal;
  font-weight: 300;
  line-height: 1.5;
  margin-block-start: 30px;
  margin-block-end: 30px;
}
h2 {
  display: block;
  font-size: 22px;
  font-style: normal;
  font-weight: 300;
  line-height: normal;
  margin-top: 0;
  margin-bottom: 8px;
}
h3 {
  font-size: 16px;
  font-weight: 400;
  margin-top: 32px;
  margin-bottom: 0;
}
p {
  max-width: 700px;
  font-weight: normal;
  font-size: 16px;
  line-height: 1.6;
  text-align: justify;
  margin-top: 0;
  margin-bottom: 0;
  padding: 0;
}
hr {
  max-width: 700px;
  margin: 20px 0;
  border: none;
  border-top: 1px solid #e0e0e0;
}
li {
  font-style: normal;
  font-weight: normal;
  font-size: 16px;
  line-height: 1.6;
  color: #121212;
}
/* Sekcje */
section {
  margin-bottom: 48px;
}
/* Wpisy papierów */
.paper {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 0 8px;
}
.paper p {
  margin: 0;
  padding: 0;
}
.paper-title {
  font-style: italic;
  font-size: 16px;
  font-weight: 400;
}
.paper-venue {
  font-size: 14px;
  font-weight: 600;
  color: #555;
  margin-bottom: 8px;
}
.paper-authors {
  font-size: 14px;
  color: #444;
}
.paper-abstract {
  font-size: 15px;
  line-height: 1.6;
  color: #333;
  padding-top: 4px;
}
/*Dane kontaktowe */
.contact {
  display: flex;
  width: 215px;
  flex-direction: column;
  align-items: flex-start;
  gap: 30px;
  position: fixed;
}
#profile {
  width: 100%;
  border-radius: 215px;
  background: url(<path-to-image>) #f4f5f6 0px -6.043px / 100% 133.333% no-repeat;
}
.contack_text {
  display: flex;
  height: 176px;
  flex-direction: column;
  align-items: flex-start;
  gap: 15px;
  align-self: stretch;
}
.contack_element {
  display: flex;
  justify-content: flex-start;
  align-items: center;
  gap: 10px;
}

/* ===================== RESPONSIVE ===================== */

/* Tablet (max 1024px) */
@media (max-width: 1024px) {
  section {
    scroll-margin-top: 80px;
  }

  .menu_item--mobile {
    display: block;
  }
  body {
    display: flex;
    flex-direction: column;
    margin: 0;
    padding: 80px 30px 20px;
    gap: 0;
  }

  nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: #f4f5f6;
    z-index: 100;
    width: 100%;
    padding: 16px 30px;
    display: flex;
    flex-direction: row;
    align-items: center;
    box-sizing: border-box;
  }

  #nav-icon4 {
    display: block;
  }

  #menu-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: #f4f5f6;
    flex-direction: column;
    gap: 0;
    padding: 8px 30px 16px;
    box-sizing: border-box;
    z-index: 99;
  }

  #menu-links.open {
    display: flex;
  }

  #menu-links .menu_item {
    padding: 10px 0;
  }

  .contact {
    display: flex;
    position: static;
    width: 100%;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    padding: 30px 0 20px;
    border-top: 1px solid #e0e0e0;
    margin-top: 30px;
  }

  #profile {
    width: 80px;
    height: 80px;
    border-radius: 50%;
  }

  .contack_text {
    height: auto;
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
  }

  .contack_element img {
    width: 20px;
    height: 20px;
  }
}

/* Mobile (max 640px) */
@media (max-width: 640px) {
  section {
    scroll-margin-top: 75px;
  }
  body {
    display: flex;
    flex-direction: column;
    margin: 0;
    padding: 70px 20px 20px;
    gap: 0;
  }

  nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: #f4f5f6;
    z-index: 100;
    width: 100%;
    padding: 16px 20px;
    display: flex;
    flex-direction: row;
    align-items: center;
    box-sizing: border-box;
  }

  #nav-icon4 {
    display: block;
  }

  #menu-links {
    display: none;
    flex-direction: column;
    gap: 14px;
    padding-top: 14px;
    width: 100%;
  }

  #menu-links.open {
    display: flex;
  }

  .menu_item {
    font-size: 13px;
  }

  h1 {
    font-size: 18px;
    margin-block-start: 20px;
    margin-block-end: 20px;
  }

  h2 {
    font-size: 18px;
  }

  p {
    max-width: 100%;
    font-size: 15px;
    line-height: 22px;
    padding-top: 20px;
  }

  hr {
    max-width: 100%;
  }

  #publications {
    padding-top: 20px;
    padding-bottom: 20px;
  }

  .contact {
    display: flex;
    position: static;
    width: 100%;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    padding: 30px 0 20px;
    border-top: 1px solid #e0e0e0;
    margin-top: 30px;
  }

  #profile {
    width: 80px;
    height: 80px;
    border-radius: 50%;
  }

  .contack_text {
    height: auto;
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
  }

  .contack_element img {
    width: 20px;
    height: 20px;
  }

  li {
    font-size: 15px;
    line-height: 24px;
  }
}