/* css variables with fallbacks + colors in hex, rgb, hsl, named, color() wider-gamut, and color-mix() */
:root {
  --meeting-green: #8ba888; /* hex */
  --bg-cream: #f1ebe1; /* hex */
  --text-main: hsl(0, 0%, 20%); /* hsl */
  --header-white: rgb(255, 255, 255); /* rgb */
  --brand-orange: orange; /* named color */
  --p3-accent: color(display-p3 0.1 0.5 0.2); /* wider-gamut color() */
  --mixed-accent: color-mix(
    in srgb,
    var(--meeting-green),
    black 20%
  ); /* color-mix() */
  --main-accent: var(
    --meeting-green,
    darkgreen
  ); /* css variable with named fallback */
}

/* universal selector: setup box model behavior */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* id selector: targeting the specific attendance section */
#attendance {
  border-left: 6px solid var(--brand-orange); /* absolute: px */
}

/* attribute selector: styling text inputs within the form */
input[type="text"] {
  border: 1px solid var(--meeting-green);
  border-radius: 4px;
}

/* descendant combinator: targeting any section inside the main tag */
main section {
  margin-bottom: 2.5rem; /* relative: rem */
}

/* child combinator: targeting sections that are direct children of the grid layout */
.grid-layout > section {
  background-color: white;
  border-radius: 10px;
}

/* general sibling combinator: any p following an h2 */
h2 ~ p {
  color: var(--text-main);
  opacity: 0.9;
}

/* adjacent sibling combinator: the ul directly following an h3 */
h3 + ul {
  border-top: 1px dashed var(--meeting-green);
}

/* combining two selectors: paragraph element with the sr-only class */
p.sr-only {
  display: none; /* display: none */
}

/* :has() selector: highlight sections only if they contain an image */
section:has(img) {
  border: 2px solid var(--mixed-accent);
  padding: 10px;
}

form p {
  margin-bottom: 1rem; /* shorthand margin */
  display: block; /* display value */
}

.feedback-form {
  background: white;

  & fieldset {
    border: 2px solid var(--mixed-accent); /* shorthand border */
    margin: 1.5rem 0; /* shorthand margin */
    padding: 1.5rem; /* shorthand padding */
  }

  /* styling the labels/text inside the form */
  & p {
    color: var(--text-main);
    font-weight: normal;
  }

  & .submit-btn {
    background-color: var(--main-accent);
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;

    &:hover {
      background-color: var(--brand-orange);
    }
  }
}

/* element selectors */
body {
  font-family: "Roboto", sans-serif; /* 3rd party font usage */
  background-color: var(--bg-cream); /* background-color */
  color: var(--text-main);
  line-height: 1.5;
  min-height: 100vh; /* relative unit: vh */
}

/* selector list for headings */
h1,
h2,
h3 {
  color: var(--main-accent);
  letter-spacing: 0.5pt; /* absolute unit: pt */
}

/* header uses sticky position and absolute units */
header {
  position: sticky; /* position value 1 */
  top: 0;
  z-index: 100;
  background-color: var(--header-white);
  padding: 15px; /* absolute unit: px */
  border-bottom: 3px solid var(--mixed-accent);
}

h1 {
  text-align: center; /* text attribute */
  text-decoration: none; /* text attribute */
  font-size: 2.2rem; /* relative unit: rem */
}

/* flexbox layout on the attendees list */
.flex-container {
  display: flex; /* flexbox layout */
  flex-direction: row; /* flex attribute 1 */
  justify-content: space-around; /* flex attribute 2 */
  flex-wrap: wrap; /* flex attribute 3 */
  list-style: none;
  padding: 1em; /* relative unit: em */
}

/* class selector: card for the main summary */
.summary-box {
  background: white;
  width: 85%; /* relative unit: % */
  max-width: 800px; /* sizing attribute */
  min-width: 280px; /* sizing attribute */

  /* longhand margins */
  margin-top: 25px;
  margin-right: auto;
  margin-bottom: 25px;
  margin-left: auto; /* auto margin */

  /* shorthand padding */
  padding: 20px 30px;

  /* longhand border properties */
  border-style: solid;
  border-width: 1px;
  border-color: var(--meeting-green);
  border-radius: 12px; /* border-radius */
}

/* grid layout for content organization */
.grid-layout {
  display: grid; /* grid layout */
  grid-template-columns: repeat(3, 1fr); /* grid attribute 1 */
  gap: 25px; /* grid attribute 2 */
  align-items: start; /* grid attribute 3 */
  padding: 2rem;
}

/* pseudo-class: hover effects */
a:hover {
  color: var(--brand-orange);
  text-decoration: underline;
}

/* pseudo-class: active state */
.submit-btn:active {
  transform: scale(0.96);
  background-color: var(--brand-orange);
}

/* form layout using box model longhands */
fieldset {
  /* shorthand border: <width> <style> <color> */
  border: 2px solid var(--mixed-accent);
  /* shorthand margin */
  margin: 1.5rem 0;
  /* longhand padding */
  padding-top: 15px;
  padding-bottom: 15px;
  padding-left: 15px;
  padding-right: 15px;
}

textarea {
  width: 100%;
  height: 3.5cm; /* absolute unit: cm */
  display: block; /* display value 1 */
}

/* responsive image styling */
img.responsive-img {
  display: inline-block; /* display value 2 */
  max-width: 100%;
  height: auto;
}

/* footer box model inversion (shorthand padding, longhand margin) */
footer {
  background-color: var(--main-accent);
  color: white;
  position: relative; /* position value 2 */

  /* shorthand padding */
  padding: 30px 10px;

  /* longhand margin */
  margin-top: 40px;
  margin-bottom: 0;
  margin-left: 0;
  margin-right: 0;
}

/* media query: reflow layout for mobile form factors */
@media (max-width: 768px) {
  .grid-layout {
    grid-template-columns: 1fr; /* layout reflow */
  }

  .flex-container {
    flex-direction: column;
    align-items: center;
  }
}

/* hidden helper for checklist completeness */
.sr-only {
  display: none;
}