@font-face {
  font-family: "Roboto Slab";
  src: url("./fonts/RobotoSlab/RobotoSlab-Light.ttf") format("truetype");
  font-weight: 300;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "Roboto Slab";
  src: url("./fonts/RobotoSlab/RobotoSlab-Regular.ttf") format("truetype");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "Roboto Slab";
  src: url("./fonts/RobotoSlab/RobotoSlab-Medium.ttf") format("truetype");
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}

html {
  font-size: 1.125rem;
  font-family: Arial, sans-serif;
}

h1, h2, h3 {
  font-family: "Roboto Slab", Arial, sans-serif;
}

header {
  display: flex;
  justify-content: space-between;
  width: 100%;
  max-width: 68.75rem;
  margin-inline: auto;
}

nav {
  display: flex;
}

h1 {
  color: white;
  font-size: 3.5em;
}

header a {
  padding: 0 1.25rem;
  height: 3rem;
  display: flex;
  align-items: center;
}

main {
  display: grid;
  grid-template-columns: 1fr 64.75rem 1fr;
}

main > * {
  grid-column: 2;
}

#splash {
  height: 940px;
  background-image: url("./angola.jpg");
  background-size: cover;
  background-position: bottom;
  grid-column: 1/-1;
  display: grid;
  grid-template-columns: 1fr repeat(3, 21.58rem) 1fr;
  text-align: center;
  align-items: center;
  gap: 20px;
}

h1 {
  grid-column: 2/-2;
}

#buttons-textbook {
  grid-column: 2;
}

#buttons-codebook {
  grid-column: 3;
}

#buttons-quizbook {
  grid-column: 4;
}

.buttons {
  position: relative;
  display: flex;
  flex-direction: column;
  background: white;
  overflow: hidden;
  border-radius: 10px;
  font-size: 1.5rem;
  width: 100%;
}

.buttons > * {
  padding: 10px 20px;
  color: black;
  text-decoration: none;
}

.buttons > :first-child {
  padding-top: 20px;
}

.buttons:not(.mask) > :nth-last-child(2) {
  padding-bottom: 20px;
}

#masks {
  position: absolute;
}

.mask {
  padding: 0;

  position: absolute;
  background: linear-gradient(
    125deg,
    hsl(222deg 69% 26%) 0%,
    hsl(217deg 67% 30%) 11%,
    hsl(213deg 67% 34%) 22%,
    hsl(209deg 68% 37%) 33%,
    hsl(206deg 69% 40%) 44%,
    hsl(203deg 71% 43%) 56%,
    hsl(200deg 75% 46%) 67%,
    hsl(198deg 79% 49%) 78%,
    hsl(195deg 87% 50%) 89%,
    hsl(193deg 100% 50%) 100%
  );
}

.mask > a {
  color: white;
}

.mask > :last-child {
  padding-bottom: 20px;
}

#buttons-textbook > .mask {
  clip-path: url(#wave-1);
}

#buttons-codebook > .mask {
  clip-path: url(#wave-2);
}

#buttons-quizbook > .mask {
  clip-path: url(#wave-3);
}

.wave {
  transform: translateY(0.6px);
}

section {
  padding-top: 2rem;
}