/* Base Reset */
* { box-sizing: border-box; }
html, body { height: 100%; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", serif;
  background: #1b1b1b;
  color: #e6e6e6;
  line-height: 1.6;
}

/* Color tokens */
:root {
  --bg: #1b1b1b;
  --bg-elev: #242424;
  --bg-elev-2: #2c2c2c;
  --text: #e6e6e6;
  --muted: #b0b0b0;
  --primary: #7dcfff;
  --primary-600: #5fb6ff;
  --accent: #a2e57b;
  --accent-600: #84d451;
  --link: #7dcfff;
  --link-hover: #a2e57b;
  --border: #3a3a3a;
  --warning: #f6c177;
  --focus: #a2e57b;
}

/* Typography */
h1, h2, h3 { line-height: 1.25; margin: 0 0 .5rem; }
h1 { font-size: clamp(2rem, 2vw + 1.5rem, 2.5rem); }
h2 { font-size: clamp(1.5rem, 1.2vw + 1rem, 2rem); }
h3 { font-size: clamp(1.25rem, 1vw + .75rem, 1.75rem); }
p { margin: .75rem 0 0; color: var(--text); }
small, .muted { color: var(--muted); }

/* Layout */
.container { width: min(1100px, 92%); margin: 0 auto; }
.section { padding: clamp(2rem, 4vw, 4rem) 0; }
.stack > * + * { margin-top: var(--stack-space, 1rem); }
.grid { display: grid; gap: 1rem; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(27, 27, 27, 0.8);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  padding: .75rem 0;
}
.brand { font-weight: 600; color: var(--text); }
.brand small { display: block; font-weight: 400; color: var(--muted); }

/* Nav */
.nav { display: flex; gap: .75rem; flex-wrap: wrap; }
.nav a {
  color: var(--link); text-decoration: none; padding: .4rem .6rem; border-radius: .5rem;
}
.nav a:hover { color: var(--link-hover); background: var(--bg-elev); }
.nav a:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }

/* Hero */
.hero { background: var(--bg); }
.hero-inner { padding: clamp(2rem, 6vw, 5rem) 0; }
.hero p { max-width: 75ch; }

/* Cards/Sections */
.section-alt { background: var(--bg-elev); }
.section-contrast { background: var(--bg-elev-2); }
.card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: .75rem;
  padding: 1rem;
}

/* Buttons */
.button {
  display: inline-flex; align-items: center; gap: .5rem;
  background: var(--bg-elev);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: .6rem;
  padding: .6rem .9rem;
  cursor: pointer;
  transition: background .2s ease, border-color .2s ease, color .2s ease;
}
.button:hover { background: #2a2a2a; border-color: #4a4a4a; color: var(--link-hover); }
.button:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.button.primary { background: var(--primary); color: #0b1220; border-color: transparent; }
.button.primary:hover { background: var(--primary-600); }

/* Dropdown-like buttons */
.button[aria-controls] {
  justify-content: space-between;
  padding-right: 2rem;
  position: relative;
}
.button[aria-controls]::after {
  content: "\25BE"; /* ▾ */
  position: absolute;
  right: .6rem;
  font-size: .9em;
  color: var(--muted);
  transition: transform .2s ease, color .2s ease;
}
.button[aria-controls]:hover::after { color: var(--link-hover); }
.button[aria-expanded="true"]::after { transform: rotate(180deg); }

/* Dropdown menu panel */
.button + .card {
  margin-top: .4rem;
  box-shadow: 0 12px 24px rgba(0,0,0,.35), 0 2px 8px rgba(0,0,0,.25);
  border-radius: .6rem;
  padding: .5rem .75rem;
}
.button + .card ul.clean { padding-left: 0; }
.button + .card ul.clean li { margin: .3rem 0; }

/* Accordion */
.accordion { display: grid; gap: .75rem; }
.accordion summary {
  list-style: none;
  cursor: pointer;
}
.accordion summary::-webkit-details-marker { display: none; }
.accordion details {
  border: 1px solid var(--border);
  border-radius: .6rem;
  background: var(--bg-elev);
  padding: .25rem .5rem;
}
.accordion details[open] { background: #262626; }
.accordion .summary {
  display: flex; align-items: center; justify-content: space-between;
  padding: .5rem .5rem;
  color: var(--text);
}
.accordion .content { padding: 0 .75rem .75rem; }

/* Lists */
ul.clean { list-style: none; padding-left: 1rem; }
ul.clean li { margin: .4rem 0; }

/* Links */
a { color: var(--link); text-decoration: none; }
a:hover { color: var(--link-hover); }
a:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }

/* Footer */
footer { color: var(--muted); border-top: 1px solid var(--border); padding: 1rem 0; }

/* Utilities */
.hidden { display: none; }
.visually-hidden {
  position: absolute !important;
  height: 1px; width: 1px;
  overflow: hidden; clip: rect(1px, 1px, 1px, 1px);
  white-space: nowrap;
}

/* Responsive tweaks */
@media (max-width: 640px) {
  .header-inner { flex-direction: column; align-items: flex-start; gap: .5rem; }
}