/*Universal selector + box model*/
* {
  margin: 0;
  padding: 0.2rem;
  box-sizing: border-box;
}
:root {
  --primary-color: hsl(220, 70.21%, 18.43%); /*color using hsl*/
  --color-space: color(srgb 0.2 0.6 1 / 0.8); /*color using color()*/
  --color-mix: color-mix(
    in srgb,
    var(--color-space),
    rgb(59, 168, 135)
  ); /*color using color-mix()*/
}
body {
  background-color: var(
    --primary-color,
    blue
  ); /*css variables and fallbacks. Color using color name*/
}
/*Class selector*/
.roboto {
  font-family: "Roboto", sans-serif;
  font-optical-sizing: auto;
  font-weight: 400;
  font-style: normal;
  font-variation-settings: "width" 100;
}

header,
main,
footer {
  background-color: #eecd9b; /*background-color and color using hex code*/
}

/*--Units: relative and absolute--*/
main {
  max-width: 900px; /* px-absolute 1*/
  min-width: 150pt; /* pt-absolute 2*/
  height: auto;
  width: 80%; /* %-relative 1*/
  margin: 0 auto; /* auto margin*/
}

/*Padding longhand + ID selector*/
#team-members {
  padding-top: 1rem; /* rem-relative 2*/
  padding-bottom: 1rem;
  padding-left: 0.5cm; /* cm-absolute 3*/
  padding-right: 0.5cm;
}

/*Padding shorthand*/
section {
  padding: 1rem 1.5rem;
  scroll-margin-top: 147.4px;
  border: 2px dashed rgb(240, 60, 180); /*border shorthand*/
}

/*Margin longhand*/
header {
  margin-top: 0;
  margin-right: 0;
  margin-bottom: 1em; /*em-relative 3*/
  margin-left: 0;
}

/*Margin shorthand*/
footer {
  margin: 2rem 0 0 0;
}

/*Border longhand*/
#agenda {
  border-style: solid;
  border-color: rgba(240, 60, 180, 0.8); /*color using rgba()*/
  border-width: 2px;
  border-radius: 8px;
}

/* Text */
h1,
h2,
h3 {
  text-align: center; /*Text-align*/
  color: var(--primary-color, navy); /*Text color*/
}
nav a {
  text-decoration: none; /*Text decoration*/
  color: var(--primary-color, navy); /*Text color*/
  display: inline-block; /*display 1: inline-block*/
}

footer small {
  display: block; /*display 2: block*/
}

/* Sizing */
img {
  width: 100%; /*width*/
  height: auto; /*Height*/
  max-width: 220px; /*max-width*/
  min-width: 150px; /*min-width*/
}

/*Position*/
header {
  position: sticky; /*position: sticky*/
  top: 0;
  z-index: 10;
}

#interest-form {
  position: relative; /*position: relative*/
}

/*Pseudo-classes + pseudo-class selector*/
nav a:hover {
  background-color: var(--color-mix, lightgray); /*using color-mix variable*/
  border-radius: 4px;
}

button:active {
  opacity: 0.8;
}

/* Layout: flexbox */
nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 3rem;
}

/* Layout: grid */
#events {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr; /*3 equal columns*/
  gap: 1rem;
  align-items: start;
}

/*Attribute selector*/
input[type="text"] {
  border-style: solid;
  border-width: 1px;
  border-color: rgb(240, 60, 180);
}

/*Combinators*/
section p {
  line-height: 1.6;
} /*Descendant combinator*/
main > section {
  margin-bottom: 2rem;
} /*Child combinator*/
h2 ~ p {
  color: var(--primary-color, navy);
} /*General sibling combinator*/
h2 + p {
  font-weight: bold;
} /*Adjacent sibling combinator*/
body.roboto {
  letter-spacing: 0.01em;
} /*combining 2 selectors*/

/* New selectors */
/* :has() */
fieldset:has(input:checked) {
  border-color: rgb(240, 60, 180);
}
/*nested selectors */
#interest-form {
  & button[type="submit"] {
    background-color: var(--primary-color, navy);
    color: white;
    &:hover {
      opacity: 0.85;
    }
  }
}

video,
audio {
  max-width: 100%;
  height: auto;
  max-width: 600px;
  width: 100%;
  display: block;
  margin: auto;
}
/*Media queries*/
/*For small screens*/
@media (max-width: 600px) {
  nav {
    flex-direction: column;
    gap: 1rem;
  }
  #events {
    grid-template-columns: 1fr; /*1 column on small screens*/
  }
  section {
    scroll-margin-top: 350.75px;
  }
}

/* For medium screens*/
@media (min-width: 601px) and (max-width: 1024px) {
  #events {
    grid-template-columns: 1fr 1fr; /*2 columns on medium screens*/
  }
}