:root {
  --clr-lime: rgb(121, 183, 50);          /* solid */
  --clr-lime-50: rgba(121, 183, 50, 0.5); /* 50% transparent */
  --clr-teal: rgb(114, 185, 197);
  --clr-bluegrey: rgb(61, 68, 104);
  --clr-sky: rgb(197, 224, 231);
  --clr-aqua: rgb(101, 192, 212);
  --clr-grey: rgb(191, 191, 191);

  --clr-bg-main: var(--clr-sky);                /* background of page */
  --clr-header-footer: var(--clr-teal);         /* nav and footer */
  --clr-content-block: var(--clr-grey);         /* content sections */
  --clr-text: #2A3132;

  --ff-body: 'Montserrat', sans-serif;
  --ff-heading: 'Inter', sans-serif;

  --fs-base: 1.25rem;
  --fs-large: 1.75rem;
  --fs-h1: 2.5rem;
  --fs-h2: 1.875rem;
}

/* Navigation Styles */
.nav-bar {
  background-color: var(--clr-header-footer);
  background-size: cover;
  background-position: center;
  padding: 0.5rem 0;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
}

.nav-list {
  display: flex;
  justify-content: center;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 0.5rem;
}

.nav-list a {
  background-color: rgba(0,0,0,0.8);
  color: #fff;
  padding: 0.5rem 1rem;
  text-decoration: none;
  font-weight: bold;
  border-radius: 0.25rem;
  transition: background-color 0.3s ease;
}

.nav-list a:hover{
  background-color: rgba(0,0,0,0.6);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem;
}

.nav-toggle {
  background: none;
  border: none;
  font-size: 2rem;
  color: white;
  display: none; /* hidden on desktop */
  cursor: pointer;
}

@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    background-color: rgba(0, 0, 0, 0.8);
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
  }

  .nav-list.open {
    display: flex;
  }
}

body {
  font-family: var(--ff-body);
  font-size: var(--fs-base);
  color: var(--clr-text);
  background-color: var(--clr-bg-main);
  margin: 0;
  padding-top: 10rem; 
}

.site-footer {
  background-color: var(--clr-header-footer);
  color: white;
  text-align: center;
  padding: 1rem 2rem;
  font-size: 0.9rem;
}

.main-header {
  margin: 1rem auto;
  padding: 1rem;
  max-width: 900px;
  font-size: var(--fs-large);
}

.content-block {
  background-color: var(--clr-content-block);
  margin: 2rem auto;
  padding: 1.5rem;
  max-width: 1250px;
  border-radius: 12px;
  box-shadow: 2px 2px 8px rgba(0,0,0,0.1);
}

.acknowledgement {
  text-align: center;
  margin: 2rem auto;
  padding: 1.5rem;
  max-width: 900px;
  background-color: var(--clr-content-block);
  border-radius: 12px;
}

h1, h2 {
  text-align: center;
}

h1 {
  font-size: var(--fs-h1);
  font-family: var(--ff-heading);
  margin-bottom: 1rem;
}

h2 {
  font-size: var(--fs-h2);
  font-family: var(--ff-heading);
  margin-top: 1rem;
  margin-bottom: 1rem;
}

p {
  line-height: 1.6;
  margin-bottom: 1rem;
}

li {
  line-height: 1.6;
  margin-bottom: 1rem;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 1rem auto;
}

.thumbnails {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-top: 2rem;
}

.thumb {
  width: 100px;
  height: auto;
  cursor: pointer;
  transition: transform 0.3s ease;
}

.thumb:hover {
  transform: scale(1.2);
}

/* Lightbox overlay */
.lightbox {
  display: none;
  position: fixed;
  z-index: 2000;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0, 0, 0, 0.8);
  justify-content: center;
  align-items: center;
  flex-direction: column;
}

.lightbox-img {
  max-width: 90%;
  max-height: 80%;
}

.lightbox .close,
.lightbox .prev,
.lightbox .next {
  position: absolute;
  color: white;
  font-size: 2rem;
  background: none;
  border: none;
  cursor: pointer;
}

.close { top: 20px; right: 30px; }
.prev { top: 50%; left: 20px; transform: translateY(-50%); }
.next { top: 50%; right: 20px; transform: translateY(-50%); }

.image-text {
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 1rem;
}