:root {
  --blue: #89c4b2;
  --blue-light: #b6e1d4;
  --green-dark: #005236;
  --green: #1d7c34;
  --green-light: #3ea536;
  --green-background: #b1d6cb;
  --yellow: #d2a61b;
  --spacing-unit: 1rem;
  --container-width: 136rem;
  --container-width-small: 76rem;
}

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 62.5%;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: "bio-sans", sans-serif;
  line-height: 1.5;
  margin: 0;
  padding: 0;
  background-image: url("https://biodiversityleiden.org/assets/background.webp");
  background-position: center top;
  background-repeat: repeat-y;
  background-size: 100% auto;
  background-attachment: scroll;
}

[tabindex="-1"] {
  outline: none !important;
}

:focus {
  outline: 3px solid var(--green);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

img {
  border: none;
  max-width: 100%;
}

section {
  padding: 4rem 6rem;
}

.no-top {
  padding-top: 0;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 0;
  font-weight: 700;
  line-height: 1;
}

h1 {
  font-size: 8rem;
  color: var(--dark-green);
  margin-bottom: 4rem;
  letter-spacing: -2px;
  text-align: center;
}

h2 {
  font-size: 2.8rem;
  margin-bottom: 1rem;
  color: var(--yellow);
  letter-spacing: -2px;
  text-transform: uppercase;
}

h3 {
  font-size: 2.6rem;
  margin-bottom: 1.2rem;
  color: var(--dark-green);
}

h4 {
  font-size: 1.8rem;
  margin-bottom: 1rem;
}

p,
ul,
ol,
a {
  font-size: 2rem;
  margin-bottom: 2rem;
  line-height: 1.4;
  color: var(--green);
}

a:hover {
  text-decoration: none;
}

ul,
ol {
  padding-left: 2rem;
}
.green {
  color: var(--green);
}

.yellow {
  color: var(--yellow);
}

.blue {
  color: var(--blue);
}

.green-light {
  color: var(--green-light);
}

.green-background {
  background-color: var(--green-background);
}

.green-background p,
.green-background a {
  color: var(--green-dark);
}

.page-wrapper {
  max-width: 1024px;
  margin: 34% auto 0;
  background-color: white;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
  min-height: 100vh;
}

.content {
  margin: 0 auto;
}

.site-logo {
  display: block;
  width: 230px;
  margin: 40px auto;
}

.two-column {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
}

.column {
  flex: 1;
  min-width: 250px; 
}

.intro {
  font: bold 32px / 1.2 'bio-sans';
  color: var(--green);
}

.smartphone {
  position: relative;
  width: 360px;
  margin: auto;
  border: 16px black solid;
  border-top-width: 60px;
  border-bottom-width: 60px;
  border-radius: 36px;
  cursor: pointer;
}

.smartphone:before {
  content: '';
  display: block;
  width: 60px;
  height: 5px;
  position: absolute;
  top: -30px;
  left: 50%;
  transform: translate(-50%, -50%);
  background: #333;
  border-radius: 10px;
}

.smartphone:after {
  content: '';
  display: block;
  width: 35px;
  height: 35px;
  position: absolute;
  left: 50%;
  bottom: -65px;
  transform: translate(-50%, -50%);
  background: #333;
  border-radius: 50%;
}

.smartphone-content {
  width: 100%;
  height: 100%;
  background: white;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
}

.smartphone video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.obsidentify {
  box-shadow: rgba(32, 71, 75, 0.1) 0px 0px 40px 0px, rgba(32, 71, 75, 0.05) 0px 6px 6px 0px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  background: rgb(255, 255, 255);
  padding: 8rem 4rem;
  border-radius: 1.6rem;
  gap: 5%;
}

.obsidentify-image {
  width: 20%;
}

.obsidentify-content {
  width: 70%;
}

.obsidentify h2 {
  color: var(--green);
}

.obsidentify p {
  color: #333;
}

.obsidentify .button {
  font-size: 1.8rem;
  color: rgb(255, 255, 255);
  display: inline-block;
  position: relative;
  margin-top: 20px;
  background: rgb(0, 102, 178);
  padding: 8px 40px;
  border-radius: 1.2rem;
  text-decoration: none;
}

.bg-image-section {
  background-size: cover;
  background-position: center;
  min-height: 500px;
}

.calendar-cards {
  display: grid;
  grid-template-columns: 47% 47%;
  gap: 2% 6%;
  padding-bottom: 8rem;
}

.card {
  color: rgb(51, 51, 51);
  position: relative;
  box-shadow: rgba(32, 71, 75, 0.1) 0px 0px 40px 0px, rgba(32, 71, 75, 0.05) 0px 6px 6px 0px;
  text-decoration: none;
}

.calendar figure {
  position: relative;
}

.calendar date {
  color: var(--green-dark);
  position: absolute;
  height: 50px;
  left: -12px;
  bottom: 24px;
  box-shadow: rgba(32, 71, 75, 0.1) 0px 0px 40px 0px, rgba(32, 71, 75, 0.05) 0px 6px 6px 0px;
  background: white;
  padding: 12px 20px;
}

.card-content {
  font-size: 2rem;
  margin-bottom: 4rem;
  padding: 4rem;
}

.calendar .button {
  font-size: 1.8rem;
  color: rgb(255, 255, 255);
  display: inline-block;
  position: absolute;
  bottom: 2rem;
  background: rgb(0 82 54);
  padding: 8px 40px;
  border-radius: 1.2rem;
}

.button-svg {
  width: 18px;
  margin: 0px 0px -3px 4px;
}

.button:hover, .card:hover .button {
  background: #84b72c;
  text-decoration: none;
}

.footer {
  background: var(--green-background);
}

.logos {
  display: flex;
  flex-wrap: wrap;
  gap: 7%;
  justify-content: center;
}

.logos img {
  width: 15%;
  margin: 6rem 0;
}


@media only screen and (max-width: 425px) {
  .obsidentify-content {
    width: 100%;
  }
  section {
    padding: 4rem 2rem;
  }
}

@media only screen and (max-width: 740px) {
  .calendar-cards {
    grid-template-columns: 100%;
    gap: 1% 6%
  }
  .logos {
    gap: 20%;
  }
  .logos img {
    width: 20%;
    margin: 6rem 0;
  }
}