:root {
  --clr-1: #111111;
  --clr-2: #ffffff;

  --clr-3: #ffcc80;
  --clr-4: #ffb74a;

  --clr-paragraphs: #666666;
  --clr-headings: #333333;
  --clr-overlay: #11111180;
  --clr-c: #cccccc;
  --clr-background: #f2f2f2;
}

@font-face {
  font-family: Inter;
  src: url(../font/Inter-VariableFont.ttf);
}
@font-face {
  font-family: DMSerif;
  src: url(../font/DMSerifDisplay-Italic.ttf);
}

h1,
h2,
h3,
h4,
h5,
p,
a,
li,
button,
label {
  font-family: "Inter", sans-serif;
}

h1 {
  font-size: 1rem;
  font-weight: 400;
  line-height: 1;
}
h2 {
  font-size: 8rem;
  font-weight: 400;
  line-height: 1;
}
h3 {
  font-size: 2.5rem;
  font-weight: 400;
  line-height: 1.2;
}
h4 {
  font-size: 1.5rem;
  font-weight: 400;
  line-height: 1.2;
}

h5 {
  font-size: 0.8rem;
  font-weight: 400;

  color: var(--clr-3);
}

h1,
h2,
h3,
h4 {
  color: var(--clr-headings);
}
p,
li,
a,
button,
label {
  font-size: 1rem;
  font-weight: 300;

  color: var(--clr-paragraphs);
}

a {
  color: var(--clr-1);
  transition: 0.3s;
}
a:hover {
  color: var(--clr-3);
}

::-webkit-scrollbar {
  width: 0.5rem;
  background: var(--clr-1);
}
::-webkit-scrollbar-track {
  border-left: none;
}
::-webkit-scrollbar-thumb {
  background: var(--clr-c);
  border: solid 2px var(--clr-1);
  border-radius: 1rem;
}

/*-- reset --*/

* {
  margin: 0;
  padding: 0;
  list-style: none;
  text-decoration: none;
  box-sizing: border-box;
  scroll-behavior: smooth;
}

/*-- setup --*/

body {
  font-size: 1rem;
  font-weight: 400;
  font-family: "Inter", sans-serif;
  line-height: 1.5;
  letter-spacing: 0.1rem;
  color: var(--clr-1);
  background-color: var(--clr-2);

  overflow-x: hidden;
}

header,
footer,
section {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

section {
  padding: 8rem 2rem;
}
.container {
  width: 1600px;

  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.description {
  width: 40%;

  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 0.5rem;

  text-align: center;

  margin-bottom: 5rem;
}

/*-- buttons --*/

.btn-flex {
  display: flex;
  flex-direction: row;
  justify-content: start;
  align-items: center;
  gap: 2rem;
}

button {
  font-size: 1rem;
  font-weight: 400;

  max-width: 320px;
  padding: 0.5rem 2rem;

  border: none;
  border-radius: 2rem;

  transition: 300ms;
  cursor: pointer;
  white-space: nowrap;
}
button:hover {
  transform: translateY(-0.1rem);
  filter: brightness(90%);
}

.btn-1 {
  color: var(--clr-1);
  background-color: var(--clr-3);
  background: linear-gradient(180deg, var(--clr-3), var(--clr-4));
  border: solid 1px var(--clr-4);
}
.btn-2 {
  color: var(--clr-1);
  background-color: var(--clr-3);
  background: linear-gradient(180deg, var(--clr-3), var(--clr-4));
  border: solid 1px var(--clr-4);
}
.btn-3 {
  padding: 0.5rem 0;

  color: var(--clr-1);
  background-color: transparent;
  border: none;

  text-decoration: underline;
}
.btn-4 {
  font-size: 1rem;
  padding: 0;

  color: var(--clr-c);
  background-color: transparent;
  border: none;

  text-decoration: underline;
}

.underline {
  text-decoration: underline;
  text-underline-offset: 0.2rem;
}

/*-- header --*/
/*-- header --*/
/*-- header --*/

#header {
  position: fixed;
  z-index: 10;
  top: 0;

  width: 100%;
  padding: 1rem 2rem;

  color: var(--clr-2);
  background-color: transparent;

  animation: headerScroll linear forwards;
  animation-timeline: view();
  animation-range-start: 120svh;
  animation-range-end: 150svh;
}
@keyframes headerScroll {
  100% {
    background-color: var(--clr-3);
    box-shadow: 0 0 0.5rem var(--clr-overlay);
  }
}

#header a,
#header h1 {
  color: var(--clr-2);

  animation: headerLinksScroll linear forwards;
  animation-timeline: view();
  animation-range-start: 120svh;
  animation-range-end: 150svh;
}
@keyframes headerLinksScroll {
  100% {
    color: var(--clr-1);
  }
}

#header-box {
  width: 100%;

  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: center;
}

#logomark {
  display: flex;
  flex-direction: row;
  justify-content: start;
  align-items: center;
  gap: 0.5rem;
}
#logomark > img {
  width: 1.5rem;
}

#header #logomark > img {
  animation: headerLogoScroll linear forwards;
  animation-timeline: view();
  animation-range-start: 120svh;
  animation-range-end: 150svh;
}
@keyframes headerLogoScroll {
  100% {
    filter: invert(80%);
  }
}

#main-menu {
  display: flex;
  flex-direction: row;
  justify-content: start;
  align-items: center;
  gap: 2rem;
}
#main-menu a:hover {
  text-decoration: underline;
  text-underline-offset: 0.2rem;
}

#mobile-btn {
  display: none;

  padding: 0;
  background-color: transparent;
}
#mobile-btn img {
  width: 1.2rem;

  animation: headerLogoScroll linear forwards;
  animation-timeline: view();
  animation-range-start: 120svh;
  animation-range-end: 150svh;
}

#mobile-menu {
  position: absolute;
  z-index: -1;
  top: 0;
  left: 0;

  width: 100vw;
  height: 100svh;
  padding: 5rem 2rem 2rem;

  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: start;

  background-color: var(--clr-1);

  transform: translateX(+100vw);
  transition: 300ms;

  animation: mobileMenuScroll linear forwards;
  animation-timeline: view();
  animation-range-start: 120svh;
  animation-range-end: 150svh;
}
@keyframes mobileMenuScroll {
  100% {
    background-color: var(--clr-3);
  }
}

#mobile-menu > ul li {
  margin-bottom: 0.5rem;
}

/*-- footer --*/
/*-- footer --*/
/*-- footer --*/

#footer {
  padding: 5rem 2rem 2rem;

  color: var(--clr-2);
  background-color: var(--clr-1);
}
#footer h1,
#footer p,
#footer a {
  color: var(--clr-2);
}

#footer a:hover {
  color: var(--clr-3);
}

#footer-box {
  width: 100%;

  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: start;
}
#footer-box > div:nth-child(1) {
  width: 20rem;
  display: flex;
  flex-direction: column;
  justify-content: start;
  align-items: start;
  gap: 1rem;
}
#footer-box > div:nth-child(1) p {
  font-size: 0.8rem;
  line-height: 1;
}

#footer-box > div:nth-child(2) {
  display: flex;
  flex-direction: row;
  justify-content: end;
  align-items: start;
  gap: 5rem;
}
#footer-box > div:nth-child(2) ul {
  text-align: right;
}
#footer-box > div:nth-child(2) ul p {
  margin-bottom: 0.5rem;
}
#footer-box > div:nth-child(2) ul li a {
  font-size: 0.8rem;
}

.author {
  width: 100%;
  margin-top: 2rem;
  padding-top: 1rem;

  border-top: solid 1px var(--clr-c);

  text-align: center;
}
.author p {
  font-size: 0.8rem;
}