/* ── Reset & Base ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --black: #ffffff; --off-black: #f5f5f5; --dark: #ebebeb; --mid: #d5d5d5;
  --light: #888888; --white: #1a1a1a; --accent: #5ab3cc;
  --font-sans: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}
html { scroll-behavior: smooth; }
body { background: var(--black); color: var(--white); font-family: var(--font-sans); overflow-x: hidden; }
a { color: inherit; text-decoration: none; }

/* ── Buttons ── */
.btn { display: inline-block; padding: .75rem 2rem; font-size: .7rem; letter-spacing: .15em; text-transform: uppercase; font-weight: 700; transition: .2s; }
.btn-primary { background: var(--accent); color: var(--white); }
.btn-primary:hover { background: #3d96ae; }
.btn-ghost { border: 1px solid var(--light); color: var(--light); margin-left: 1rem; }
.btn-ghost:hover { border-color: var(--white); color: var(--white); }

/* ── Footer ── */
footer { background: var(--off-black); padding: 2rem 2.5rem; display: flex; align-items: center; justify-content: space-between; border-top: 1px solid var(--mid); flex-wrap: wrap; gap: 1rem; }
.footer-logo { font-size: .7rem; font-weight: 700; letter-spacing: .2em; text-transform: uppercase; }
.footer-copy { font-size: .65rem; color: var(--light); }
.social-links { display: flex; gap: 1.25rem; }
.social-links a { font-size: .65rem; letter-spacing: .15em; text-transform: uppercase; color: var(--light); transition: color .2s; }
.social-links a:hover { color: var(--white); }

/* ── Light-theme overrides ── */
.btn-primary { color: #fff; }
.btn-ghost { border-color: #aaa; color: #555; }
.btn-ghost:hover { border-color: #111; color: #111; }
.hero-title { color: #fff; }
.hero-sub { color: rgba(255,255,255,.8); }
.hero-scroll { color: rgba(255,255,255,.65); }
.hero-scroll::before { background: rgba(255,255,255,.65); }

/* ── Side Nav ── */
.sidenav {
  position: fixed; top: 0; left: 0; bottom: 0; width: 240px;
  background: #fff; border-right: 1px solid #e8e8e8;
  display: flex; flex-direction: column; z-index: 1000;
  transition: transform .3s ease; overflow-y: auto;
}
.sidenav-logo { padding: 1.5rem 1.5rem 1.25rem; border-bottom: 1px solid #efefef; display: block; }
.sidenav-logo .logo-first { font-size: .55rem; font-weight: 400; letter-spacing: .3em; color: var(--accent); text-transform: uppercase; display: block; }
.sidenav-logo .logo-last { font-size: 1rem; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; color: #111; margin-top: .15rem; display: block; }
.sidenav-logo .logo-tag { font-size: .48rem; letter-spacing: .18em; text-transform: uppercase; color: #bbb; margin-top: .3rem; display: block; }
.sidenav-section-label { font-size: .48rem; letter-spacing: .28em; text-transform: uppercase; color: #ccc; padding: 1.25rem 1.5rem .4rem; display: block; }
.sidenav-links { list-style: none; display: flex; flex-direction: column; }
.sidenav-links a {
  display: block; padding: .5rem 1.5rem;
  font-size: .68rem; letter-spacing: .1em; text-transform: uppercase; color: #666; font-weight: 500;
  transition: color .15s, background .15s; border-left: 2px solid transparent;
}
.sidenav-links a:hover { color: #111; background: #f7f7f7; }
.sidenav-links a.active { color: #111; border-left-color: var(--accent); background: rgba(90,179,204,.05); font-weight: 700; }
.sidenav-group { display: flex; flex-direction: column; margin-top: .25rem; }
.sidenav-group-toggle {
  display: flex; align-items: center; justify-content: space-between; padding: .45rem 1.5rem;
  font-size: .5rem; letter-spacing: .22em; text-transform: uppercase; color: #bbb; font-weight: 400;
  cursor: pointer; transition: color .15s; user-select: none;
}
.sidenav-group-toggle:hover { color: #888; }
.sidenav-group-toggle.open { color: #555; }
.sidenav-group-toggle .tgl-left { display: flex; align-items: center; gap: .4rem; }
.sidenav-group-toggle .chevron { font-size: .5rem; transition: transform .2s; color: #ccc; }
.sidenav-group-toggle.open .chevron { transform: rotate(90deg); color: #aaa; }
.sidenav-sub { display: none; flex-direction: column; }
.sidenav-sub.open { display: flex; }
.sidenav-sub a {
  padding: .4rem 1.5rem .4rem 2.5rem; font-size: .65rem; letter-spacing: .08em;
  text-transform: uppercase; color: #999; transition: color .15s; border-left: 2px solid transparent;
  position: relative;
}
.sidenav-sub a::before { content: ''; position: absolute; left: 1.5rem; top: 50%; width: 5px; height: 1px; background: #ddd; }
.sidenav-sub a:hover { color: #222; }
.sidenav-sub a:hover::before { background: #aaa; }
.sidenav-sub a.active { color: #111; border-left-color: var(--accent); font-weight: 600; }
.sidenav-sub a.active::before { background: var(--accent); }
.sidenav-divider { border: none; border-top: 1px solid #f0f0f0; margin: .75rem 1.5rem .25rem; }
.sidenav-util { list-style: none; display: flex; flex-direction: column; }
.sidenav-util a {
  display: block; padding: .4rem 1.5rem; font-size: .6rem; letter-spacing: .12em;
  text-transform: uppercase; color: #bbb; transition: color .15s;
}
.sidenav-util a:hover { color: #555; }
.sidenav-util a.active { color: var(--accent); }
.sidenav-footer { margin-top: auto; padding: 1.25rem 1.5rem; border-top: 1px solid #efefef; }
.sidenav-footer a {
  display: block; font-size: .6rem; letter-spacing: .15em; text-transform: uppercase;
  text-align: center; border: 1px solid var(--accent); color: var(--accent);
  padding: .6rem; transition: background .2s, color .2s;
}
.sidenav-footer a:hover { background: var(--accent); color: #fff; }
.sidenav-toggle {
  display: none; position: fixed; top: 1rem; left: 1rem; z-index: 1100;
  background: #fff; border: 1px solid #ddd; color: #111;
  width: 2.5rem; height: 2.5rem; align-items: center; justify-content: center;
  font-size: 1.1rem; cursor: pointer; font-family: inherit;
}
.sidenav-overlay { display: none; position: fixed; inset: 0; background: rgba(0,0,0,.4); z-index: 999; }
@media (max-width: 860px) {
  .sidenav { transform: translateX(-100%); }
  .sidenav.open { transform: translateX(0); }
  .sidenav-toggle { display: flex; }
  .sidenav-overlay.open { display: block; }
  body { margin-left: 0 !important; }
}
body { margin-left: 240px; }

/* ── Responsive (shared) ── */
@media (max-width: 900px) {
  footer { flex-direction: column; align-items: flex-start; }
}