:root {
  --bg: #ffffff;
  --fg: #000000;
  --muted: #6f6f6f;
  --border: #e5e5e5;
  --chip-bg: #f3f3f3;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { font-family: 'Inter', sans-serif; background: var(--bg); color: var(--fg); line-height: 1.75; }

/* Utilities */
.container { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; }
.section { padding: 4.5rem 0; border-bottom: 1px solid var(--border); }
.overline { text-transform: uppercase; font-size: .75rem; letter-spacing: .15em; color: var(--muted); margin-bottom: .5rem; }
.sm-title { text-transform: uppercase; font-size: .8rem; letter-spacing: .1em; color: var(--muted); margin-bottom: .75rem; }
.reveal { opacity: 0; transform: translateY(40px); transition: all .6s ease-out; }
.show { opacity: 1; transform: translateY(0); }

/* Header */
header { position: sticky; top: 0; z-index: 1000; background: var(--bg); border-bottom: 1px solid var(--border); }
nav { display: flex; justify-content: space-between; align-items: center; height: 60px; }
nav .brand {
  font-size: 1.35rem;
  font-weight: 800;
  text-decoration: none;
  color: var(--fg);
  position: relative;
}

nav .brand::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -3px;
  width: 0;
  height: 1px;
  background: var(--fg);
  transition: width .25s;
}

nav .brand:hover::after {
  width: 100%;
}

nav ul { list-style: none; display: flex; gap: 1.25rem; }
nav a { text-decoration: none; color: var(--fg); font-weight: 500; position: relative; }
nav a::after { content: ''; position: absolute; left: 0; bottom: -3px; width: 0; height: 1px; background: var(--fg); transition: width .25s; }
nav a:hover::after { width: 100%; }
.menu-toggle { display: none; font-size: 1.5rem; cursor: pointer; }

/* Dropdown (desktop) */
nav ul li { position: relative; }
nav ul li.has-dropdown > a { padding-right: 0; }
nav ul li.has-dropdown > a::before { content: none; }
nav ul li .dropdown {
  position: absolute;
  left: 0; top: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  box-shadow: 0 10px 20px rgba(0,0,0,0.08);
  overflow: hidden;
  display: block;
  max-height: 0;
  opacity: 0;
  transform: translateY(-6px);
  transition: max-height .25s ease, opacity .2s ease, transform .25s ease;
  pointer-events: none;
  z-index: 1001;
}
nav ul li .dropdown a {
  display: block;
  padding: .55rem .9rem;
  white-space: nowrap;
}
nav ul li .dropdown a:hover { background: var(--chip-bg); }
nav ul li.has-dropdown:hover > .dropdown {
  max-height: 300px;
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

/* Common button styles */
.btn-outline { 
  display: inline-flex; 
  align-items: center; 
  gap: .55rem; 
  padding: .6rem 1.25rem; 
  font-size: .9rem; 
  border: 1px solid var(--fg); 
  border-radius: 6px; 
  text-decoration: none; 
  color: var(--fg); 
  transition: background .2s, color .2s; 
}
.btn-outline:hover { background: var(--fg); color: var(--bg); }

/* Footer */
footer { text-align: center; padding: 2rem 0 4rem; font-size: .85rem; color: var(--muted); }

/* Responsive */
@media (max-width: 680px) {
  body {
    overflow-x: hidden;
    position: relative;
  }
  
  nav ul {
    position: fixed;
    top: 60px;
    right: 0;
    background: var(--bg);
    width: 220px;
    height: calc(100vh - 60px);
    padding: 1rem 1.5rem;
    border-left: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    transform: translateX(100%);
    transition: transform .25s ease;
    flex-direction: column;
    z-index: 999;
    box-shadow: -5px 0 15px rgba(0,0,0,0.1);
  }
  
  nav ul.open {
    transform: translateX(0);
  }
  
  /* Mobile dropdown behavior */
  nav ul li .dropdown {
    position: static;
    border: 0;
    box-shadow: none;
    background: transparent;
    max-height: 0;
    opacity: 1; /* keep text visible when opened by height */
    transform: none;
    transition: max-height .25s ease;
  }
  nav ul li .dropdown a { padding-left: 0.5rem; }
  nav ul li.has-dropdown.open > .dropdown { max-height: 200px; }
  nav ul li.has-dropdown > a::before { content: none; }

  .menu-toggle {
    display: block;
    z-index: 1000;
  }
}

/* Highlight animation */
@keyframes bubblyHighlight {
  0% { transform: scale(1); color: var(--muted); }
  50% { transform: scale(1.1); color: var(--fg); }
  100% { transform: scale(1); color: var(--muted); }
}
.sm-title.highlighted {
  animation: bubblyHighlight 0.8s ease-in-out forwards;
  display: inline-block;
}

.image-source {
  font-size: 0.8rem;
  color: var(--muted);
  margin-top: 0.25rem;
  font-style: italic;
}