html {
  background: #7ff5ff;
  line-height: 1.15;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: sans-serif;
}

input[type="search"] {
  -webkit-appearance: textfield;
  outline-offset: -2px;
}

/* ===== Main Layout ===== */
main {
  -webkit-flex: 0;
  flex-shrink: 0;
}

.main_content {
  width: 90%;      /* fills most of screen on mobile */
  max-width: 1000px; /* optional cap for desktop */
  margin: 0 auto;  /* centers content */
  height: auto;
  display: block;
  padding: 10px;   /* some breathing room on mobile */
}

/* ===== Small Block Element ===== */
.small_1 {
  width: 100%;    /* scale to mobile width */
  max-width: 200px; /* optional desktop cap */
  height: auto;   /* scale height automatically */
  display: inline-block;
  margin-right: 6px;
}

/* ===== Brighten & Darken Effects ===== */
.brighten {
  transition: filter 0.3s ease;
  display: block;
  max-width: 100%; /* responsive images */
  height: auto;
}

.brighten:hover {
  filter: brightness(200%) contrast(1.2);
}

.darken {
  transition: filter 0.3s ease;
}

.darken:hover {
  filter: brightness(50%);
}

/* ===== Headings ===== */
h2, h3, h4, h5 {
  position: relative;  /* remove top/left offsets */
  margin: 10px 0;
  text-align: center;  /* center headings on small screens */
}

h3:hover,
h4:hover,
h5:hover {
  filter: brightness(1.5);
}

/* ===== Responsive Images ===== */
img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 0 auto; /* centers images on mobile */
}

/* ===== Optional Vertical Menu ===== */
.vertical-menu {
  display: flex !important;
  flex-direction: column !important;
  align-items: center;
  gap: 15px; /* spacing between images */
  margin: 20px 0;
}

/* ===== Media Queries for Larger Screens ===== */
@media screen and (min-width: 768px) {
  .main_content {
    width: 75%; /* scales up for tablets */
  }
  .small_1 {
    width: 19%; /* restores desktop layout */
  }
}

@media screen and (min-width: 1200px) {
  .main_content {
    width: 60%; /* desktop layout */
  }
}