:root {
  --color-title: #102840;
  --color-text: #273139;
  --color-text-secondary: #8a8986;
  --color-background: #f5f5ef;
  --color-card: #ffffff;
  --color-turquoise: #28dce5;
  --color-blue-light: #bcfffb;
  --color-lavender: #939bd7;
  --color-lavender-light: #d1d5f6;
  --color-green: #c7ed58;
  --color-green-light: #e6fda2;
  --color-border: #e4e7e5;
  --shadow-card: 0 18px 38px rgba(16, 40, 64, 0.08);
  --shadow-button: 0 8px 18px rgba(16, 40, 64, 0.14);
  --radius-large: 26px;
  --radius-medium: 22px;
  --page-width: 1180px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  color-scheme: light;
  scroll-behavior: smooth;
}

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  margin: 0;
  overflow-x: hidden;
  color: var(--color-text);
  background: var(--color-background);
  font-family: "Poppins", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
}

.page-container {
  width: min(calc(100% - 72px), var(--page-width));
  margin-inline: auto;
}

.site-header {
  position: relative;
  z-index: 10;
}

.site-header__inner {
  display: grid;
  grid-template-columns: 210px 1fr 210px;
  align-items: center;
  min-height: 86px;
}

.brand {
  justify-self: start;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  width: 176px;
  height: 62px;
}

.brand__logo {
  width: 50px;
  height: 50px;
  flex: 0 0 auto;
  object-fit: contain;
}

.brand__copy {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  color: #182239;
  line-height: 1;
}

.brand__copy::after {
  position: absolute;
  top: -8px;
  right: -17px;
  width: 13px;
  height: 13px;
  border-top: 3px solid var(--color-turquoise);
  border-right: 3px solid var(--color-turquoise);
  border-radius: 2px;
  content: "";
  transform: rotate(-16deg) skew(-9deg);
}

.brand__name {
  font-size: 25px;
  font-weight: 800;
  letter-spacing: -1.3px;
}

.brand__tagline {
  margin-top: 5px;
  padding-left: 3px;
  font-size: 7px;
  font-weight: 700;
  letter-spacing: 3px;
}

.main-nav {
  grid-column: 2;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 34px;
  height: 100%;
}

.main-nav__link {
  position: relative;
  padding: 30px 0 12px;
  color: #536071;
  font-size: 14px;
  font-weight: 500;
  transition: color 180ms ease;
}

.main-nav__link::after {
  position: absolute;
  right: 0;
  bottom: 4px;
  left: 0;
  height: 3px;
  border-radius: 999px;
  background: var(--color-turquoise);
  content: "";
  opacity: 0;
  transform: scaleX(0.45);
  transition: opacity 180ms ease, transform 180ms ease;
}

.main-nav__link:hover,
.main-nav__link:focus-visible,
.main-nav__link.is-active {
  color: var(--color-title);
}

.main-nav__link:hover::after,
.main-nav__link:focus-visible::after,
.main-nav__link.is-active::after {
  opacity: 1;
  transform: scaleX(1);
}

.hub-main {
  position: relative;
  z-index: 2;
  padding-bottom: 24px;
}

.hub-intro {
  margin: 1px auto 34px;
  text-align: center;
}

.hub-intro__title {
  position: relative;
  display: inline-block;
  margin: 0;
  color: #111b32;
  font-size: clamp(38px, 3.25vw, 50px);
  font-weight: 800;
  letter-spacing: 0px;
  line-height: 1.15;
}

.hub-intro__underline {
  position: absolute;
  right: -10px;
  bottom: -9px;
  width: 190px;
  height: 8px;
  border-radius: 50%;
  border-top: 5px solid var(--color-turquoise);
  transform: rotate(4deg);
}

.hub-intro__subtitle {
  margin: 12px 0 0;
  color: #566176;
  font-size: 17px;
  font-weight: 400;
  letter-spacing: 0.1px;
}

.resource-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  grid-template-rows: 202px 218px;
  gap: 14px;
}

.resource-grid__secondary {
  display: grid;
  grid-template-columns: minmax(0, 0.93fr) minmax(0, 1.07fr);
  gap: 14px;
}

.resource-card {
  position: relative;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.45);
  border-radius: var(--radius-large);
  box-shadow: var(--shadow-card);
  isolation: isolate;
  transition: box-shadow 200ms ease, transform 200ms ease;
}

.resource-card:hover,
.resource-card:focus-visible {
  z-index: 3;
  outline: none;
  box-shadow: 0 22px 44px rgba(16, 40, 64, 0.15);
  transform: translateY(-4px);
}

.resource-card:focus-visible {
  box-shadow: 0 0 0 4px rgba(40, 220, 229, 0.35), 0 22px 44px rgba(16, 40, 64, 0.15);
}

.resource-card--flashcards {
  grid-row: 1 / 3;
  background: linear-gradient(145deg, #2bdae4 0%, #16cbd8 72%, #19c4d1 100%);
}

.resource-card--flashcards::before,
.resource-card--flashcards::after {
  position: absolute;
  z-index: -1;
  bottom: -102px;
  width: 125%;
  height: 190px;
  border-radius: 50%;
  content: "";
}

.resource-card--flashcards::before {
  left: -43%;
  background: rgba(188, 255, 251, 0.5);
  transform: rotate(9deg);
}

.resource-card--flashcards::after {
  right: -48%;
  bottom: -126px;
  background: rgba(209, 213, 246, 0.35);
  transform: rotate(-8deg);
}

.resource-card--quizzes {
  background: linear-gradient(135deg, #9ba4df 0%, var(--color-lavender) 100%);
}

.resource-card--notes {
  background: linear-gradient(145deg, #ffffff 0%, #fbfbfa 100%);
}

.resource-card--presentations {
  background: linear-gradient(135deg, #d2f75d 0%, var(--color-green) 100%);
}

.resource-card__content {
  position: relative;
  z-index: 2;
}

.resource-card__content--flashcards {
  padding: 28px 34px 0;
}

.resource-card__content--quizzes {
  width: 54%;
  padding: 28px 0 0 30px;
}

.resource-card__content--small {
  padding: 20px 22px 0;
}

.resource-card__title {
  margin: 0;
  color: #0e1831;
  font-size: 38px;
  font-weight: 800;
  letter-spacing: -1.5px;
  line-height: 1.05;
}

.resource-card__title--large {
  font-size: 52px;
  letter-spacing: -2.5px;
}

.resource-card__title--small {
  font-size: 31px;
  letter-spacing: -1.4px;
}

.resource-card--presentations .resource-card__title--small {
  font-size: 29px;
  letter-spacing: -1.2px;
}

.resource-card--presentations .resource-card__content--small {
  position: static;
  padding: 21px 22px 0;
}

.resource-card--presentations .resource-card__description--small {
  position: absolute;
  top: 73px;
  right: 17px;
  z-index: 2;
  width: 37%;
  margin: 0;
  color: #11182d;
  font-size: 14px;
  line-height: 1.45;
}
.resource-card__description {
  margin: 8px 0 0;
  color: #1f2a42;
  font-size: 14px;
  line-height: 1.45;
}

.resource-card__description--large {
  margin-top: 4px;
  font-size: 20px;
  line-height: 1.35;
}

.resource-card__description--small {
  margin-top: 3px;
  font-size: 13px;
}

.resource-card__image {
  position: absolute;
  z-index: 1;
  object-fit: contain;
  pointer-events: none;
  user-select: none;
}

.resource-card__image--flashcards {
  right: 18px;
  bottom: 57px;
  left: 18px;
  width: calc(100% - 36px);
  height: 250px;
}

.resource-card__image--quizzes {
  right: 15px;
  bottom: 0px;
  width: 50%;
  height: 190px;
}

.resource-card__image--notes {
  right: 15px;
  bottom: 0px;
  width: 84%;
  height: 139px;
}

.resource-card__image--presentations {
  right: auto;
  bottom: 9px;
  left: 12px;
  width: 57%;
  height: 137px;
}

.resource-card__button {
  position: absolute;
  z-index: 3;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  min-height: 48px;
  padding: 0 24px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  white-space: nowrap;
  box-shadow: var(--shadow-button);
}

.resource-card__button--dark {
  bottom: 21px;
  left: 30px;
  color: #ffffff;
  background: var(--color-text);
}

.resource-card__button--light {
  bottom: 25px;
  left: 30px;
  min-height: 44px;
  color: #192239;
  background: #ffffff;
}

.resource-card__button--compact {
  bottom: 16px;
  left: 18px;
  min-height: 39px;
  padding: 0 16px;
  gap: 9px;
  font-size: 12px;
  color: #192239;
  background: #ffffff;
}

.arrow {
  font-size: 21px;
  font-weight: 400;
  line-height: 1;
  transition: transform 180ms ease;
}

.resource-card:hover .arrow,
.resource-card:focus-visible .arrow {
  transform: translateX(4px);
}

.resource-card__round-button {
  position: absolute;
  right: 11px;
  bottom: 11px;
  z-index: 3;
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 50%;
  color: #172139;
  background: #ffffff;
  box-shadow: var(--shadow-button);
  font-size: 23px;
  transition: transform 180ms ease;
}

.resource-card__round-button--presentations {
  right: 39px;
  bottom: 17px;
  left: auto;
  width: 52px;
  height: 52px;
}
.resource-card:hover .resource-card__round-button,
.resource-card:focus-visible .resource-card__round-button {
  transform: translateX(3px);
}

.resource-search {
  display: grid;
  grid-template-columns: auto 1px 1fr auto;
  align-items: center;
  min-height: 62px;
  margin-top: 14px;
  padding: 0 26px;
  border: 1px solid rgba(255, 255, 255, 0.75);
  border-radius: 20px;
  color: var(--color-text);
  background: rgba(255, 255, 255, 0.86);
  box-shadow: 0 12px 30px rgba(16, 40, 64, 0.05);
}

.resource-search__prompt {
  display: flex;
  align-items: center;
  gap: 16px;
  padding-right: 24px;
  font-size: 14px;
}

.resource-search__icon {
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border: 2px solid var(--color-title);
  border-radius: 50%;
}

.resource-search__icon svg {
  width: 17px;
  height: 17px;
  fill: none;
  stroke: var(--color-title);
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.8;
}

.resource-search__divider {
  width: 1px;
  height: 30px;
  background: var(--color-border);
}

.resource-search__suggestion {
  padding-left: 25px;
  color: #657083;
  font-size: 13px;
}

.resource-search__arrow {
  color: var(--color-title);
  font-size: 25px;
}

.bottom-wave {
  position: relative;
  z-index: 1;
  flex: 0 0 90px;
  width: 100vw;
  height: 90px;
  margin-top: auto;
  overflow: hidden;
}

.bottom-wave img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: fill;
}

.hub-footer {
  flex: 0 0 auto;
  padding: 28px 0 24px;
  color: var(--color-title);
  background: #bcfffb;
}

.hub-footer__content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.hub-footer p {
  margin: 0;
}

.hub-footer__brand {
  font-size: 15px;
  font-weight: 600;
}

.hub-footer__year {
  margin-top: 4px !important;
  color: var(--color-text-secondary);
  font-size: 13px;
}

.hub-footer__links,
.hub-footer__social {
  display: flex;
  align-items: center;
}

.hub-footer__links {
  gap: 18px;
}

.hub-footer__privacy {
  font-size: 15px;
}

.hub-footer__privacy:hover,
.hub-footer__privacy:focus-visible {
  text-decoration: underline;
}

.hub-footer__separator {
  color: var(--color-text-secondary);
}

.hub-footer__social {
  gap: 10px;
}

.hub-footer__icon {
  display: grid;
  width: 36px;
  height: 36px;
  place-items: center;
  color: var(--color-title);
  transition: color 180ms ease, border-color 180ms ease, transform 180ms ease;
}

.hub-footer__icon--circle {
  border: 1.7px solid currentColor;
  border-radius: 50%;
}

.hub-footer__icon:hover,
.hub-footer__icon:focus-visible {
  color: #10c0cb;
  outline: none;
  transform: translateY(-2px);
}

@media (max-width: 1180px) {
  .site-header__inner {
    grid-template-columns: 180px 1fr 80px;
  }

  .main-nav {
    gap: 24px;
  }

  .resource-card__title--large {
    font-size: 47px;
  }
}

/* Base responsive safeguard. The detailed tablet and mobile design comes later. */
@media (max-width: 900px) {
  .page-container {
    width: min(calc(100% - 40px), 720px);
  }

  .site-header__inner {
    display: flex;
    min-height: auto;
    padding-block: 16px 10px;
    flex-direction: column;
    gap: 4px;
  }

  .brand {
    width: 138px;
    height: 54px;
  }

  .brand__logo {
    width: 44px;
    height: 44px;
  }

  .brand__name {
    font-size: 22px;
  }

  .main-nav {
    flex-wrap: wrap;
    gap: 8px 24px;
  }

  .main-nav__link {
    padding: 8px 0 10px;
  }

  .hub-intro {
    margin-top: 22px;
  }

  .hub-intro__title {
    font-size: clamp(34px, 7vw, 46px);
  }

  .resource-grid {
    grid-template-columns: 1fr;
    grid-template-rows: 420px 210px 218px;
  }

  .resource-card--flashcards {
    grid-row: auto;
  }
}

@media (max-width: 620px) {
  .page-container {
    width: min(calc(100% - 28px), 520px);
  }

  .resource-grid {
    grid-template-rows: 410px 230px auto;
  }

  .resource-grid__secondary {
    grid-template-columns: 1fr;
    grid-auto-rows: 218px;
  }

  .resource-search {
    grid-template-columns: 1fr auto;
    row-gap: 6px;
    padding-block: 13px;
  }

  .resource-search__prompt {
    padding-right: 0;
  }

  .resource-search__divider {
    display: none;
  }

  .resource-search__suggestion {
    grid-column: 1 / 2;
    padding-left: 44px;
  }

  .resource-search__arrow {
    grid-column: 2;
    grid-row: 1 / 3;
  }

  .hub-footer {
    padding-block: 28px;
  }

  .hub-footer__content,
  .hub-footer__links {
    flex-direction: column;
  }

  .hub-footer__content {
    gap: 22px;
    text-align: center;
  }

  .hub-footer__links {
    gap: 14px;
  }

  .hub-footer__separator {
    display: none;
  }
}