:root {
  /* light defaults */
  --bg: #ffffff;
  --text: #121212;
  --muted: #4a4a4a;
  --accent: #00bcd4;
  --card: #fafafa;
  --border: #e5e5e5;
}

[data-theme="dark"] {
  --bg: #0f1115;
  --text: #eaecee;
  --muted: #a0a6b2;
  --accent: #00bcd4;
  --card: #151922;
  --border: #2a2f3a;
}

/* global */
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: background-color .3s ease, color .3s ease;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container { max-width: 920px; margin: 0 auto; padding: 2rem 1.25rem 3rem; }

/* header */
.hero { text-align: center; padding-top: 1rem; }
.avatar { width: 140px; border-radius: 50%; box-shadow: 0 0 18px rgba(0,188,212,.35); margin-bottom: 1rem; }
h1 { font-size: 2rem; margin: .5rem 0 0; }
h2 { font-size: 1.15rem; color: var(--accent); font-weight: 500; margin: .25rem 0 .5rem; }
.subtitle { color: var(--muted); margin: .25rem 0 1rem; }
.cta { display: flex; gap: .75rem; justify-content: center; flex-wrap: wrap; }

/* buttons */
.button-link {
  display: inline-block;
  padding: .6rem 1rem;
  border-radius: 10px;
  background: var(--accent);
  color: white;
  text-decoration: none;
  font-weight: 600;
  border: 1px solid transparent;
  transition: transform .12s ease, filter .12s ease;
}
.button-link:hover { transform: translateY(-1px); filter: brightness(1.05); }
.button-link.ghost { background: transparent; color: var(--accent); border: 1px solid var(--accent); }

/* cards & sections */
.card { background: var(--card); border: 1px solid var(--border); border-radius: 14px; padding: 1.25rem 1.1rem; margin-bottom: 1.25rem; }
h3 { border-bottom: 2px solid var(--accent); padding-bottom: .35rem; margin-top: 0; }
p { line-height: 1.6; }

/* lists */
ul { list-style: none; padding-left: 0; margin: .6rem 0; }
ul li { margin: .4rem 0; }
ul li::before { content: "▹"; color: var(--accent); padding-right: .5rem; }

/* contact */
.contact a { color: var(--accent); text-decoration: none; }
.contact a:hover { text-decoration: underline; }

/* footer */
.footer { text-align: center; color: var(--muted); margin-top: 1rem; }
.footer a { color: var(--accent); }

/* theme toggle button */
.theme-toggle {
  position: fixed; top: 1rem; right: 1rem;
  padding: .5rem .9rem; border: none; border-radius: 10px;
  background: var(--accent); color: white; cursor: pointer;
  box-shadow: 0 6px 20px rgba(0, 188, 212, .25);
}

/* Skip link for keyboard users */
.skip-link {
  position: absolute;
  left: -999px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
}
.skip-link:focus {
  position: static;
  width: auto;
  height: auto;
  padding: .5rem .75rem;
  background: var(--accent);
  color: #fff;
  border-radius: 8px;
  z-index: 1000;
}

/* Visible focus states */
a:focus, button:focus, .button-link:focus {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

a:hover, a:focus {
  text-decoration: underline;
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }
}