:root {
    --bg: #ffffff; --ink: #14181f; --muted: #5c6470; --line: #e8eaee;
    --accent: #2f5bea; --accent-soft: #eef2ff; --card-bg: #ffffff; --soft-bg: #fafbfc;
    --field-bg: #ffffff; --radius: 14px; --max: 1100px;
  }
  [data-theme="dark"] {
    --bg: #0f1217; --ink: #e8eaee; --muted: #9aa3b0; --line: #262b34;
    --accent: #5b82ff; --accent-soft: #1a2236; --card-bg: #161a21; --soft-bg: #12151b;
    --field-bg: #161a21;
  }
  html { transition: background-color .25s ease; }
  body { transition: background-color .25s ease, color .25s ease; }

  * { box-sizing: border-box; margin: 0; padding: 0; }

  /* Toggle button */
  .theme-toggle {
    width: 40px; height: 40px; border-radius: 50%;
    border: 1px solid var(--line); background: transparent; color: var(--ink);
    display: grid; place-items: center; cursor: pointer;
    transition: border-color .15s ease, color .15s ease, transform .15s ease;
  }
  .theme-toggle:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-1px); }
  /* show correct icon per theme */
  .theme-toggle .icon-sun { display: none; }
  [data-theme="dark"] .theme-toggle .icon-sun { display: block; }
  [data-theme="dark"] .theme-toggle .icon-moon { display: none; }

  body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, sans-serif;
    color: var(--ink); background: var(--bg); line-height: 1.6; -webkit-font-smoothing: antialiased;
  }
  .wrap { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
  a { color: inherit; text-decoration: none; }

  /* Nav */
  header {
    position: sticky; top: 0; z-index: 10; background: rgba(255,255,255,0.85);
    backdrop-filter: blur(10px); border-bottom: 1px solid var(--line);
  }

  .header, header { background: color-mix(in srgb, var(--bg) 85%, transparent); }

  .nav { display: flex; align-items: center; justify-content: space-between; height: 68px; }
  .logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.2rem; letter-spacing: -0.02em; }
  .nav-links { display: flex; gap: 32px; }
  .nav-links a { color: var(--muted); font-size: 0.95rem; }
  .nav-links a:hover, .nav-links a.active { color: var(--ink); }
  .btn {
    display: inline-block; background: var(--accent); color: #fff;
    padding: 11px 22px; border-radius: 999px; font-weight: 600; font-size: 0.95rem;
    border: none; cursor: pointer; transition: transform .15s ease, opacity .15s ease;
  }
  .btn:hover { transform: translateY(-1px); opacity: .92; }

  /* Contact layout */
  .contact { padding: 80px 0; }
  .contact-head { text-align: center; margin-bottom: 56px; }
  .contact-head .pill {
    display: inline-block; background: var(--accent-soft); color: var(--accent);
    font-size: .82rem; font-weight: 600; padding: 6px 14px; border-radius: 999px; margin-bottom: 20px;
  }
  .contact-head h1 { font-size: clamp(2rem, 4vw, 3rem); letter-spacing: -0.03em; margin-bottom: 14px; }
  .contact-head p { color: var(--muted); max-width: 520px; margin: 0 auto; font-size: 1.1rem; }

  .contact-grid { display: grid; grid-template-columns: 1fr 1.2fr; gap: 48px; align-items: start; }

  /* Info column */
  .info-item { display: flex; gap: 14px; padding: 18px 0; border-bottom: 1px solid var(--line); }
  .info-item:last-child { border-bottom: none; }
  .info-icon {
    flex: 0 0 42px; width: 42px; height: 42px; border-radius: 12px;
    background: var(--accent-soft); color: var(--accent); display: grid; place-items: center;
  }
  .info-item h4 { font-size: 1rem; margin-bottom: 2px; }
  .info-item p, .info-item a { color: var(--muted); font-size: .96rem; }
  .info-item a:hover { color: var(--accent); }

  /* Form column */
  form.contact-form { display: grid; gap: 16px; }
  .field label { display: block; font-size: .9rem; font-weight: 600; margin-bottom: 6px; }
  .field input, .field textarea {
    width: 100%; padding: 13px 16px; border: 1px solid var(--line);
    border-radius: 12px; font-size: .98rem; font-family: inherit; outline: none;
    transition: border-color .15s ease;
  }
  .field input:focus, .field textarea:focus { border-color: var(--accent); }
  .field textarea { resize: vertical; min-height: 130px; }
  .form-msg { font-size: .92rem; min-height: 1.2em; }
  .form-msg.ok { color: #1f9d57; }
  .form-msg.err { color: #d23b3b; }

  /* Footer */
  footer { padding: 40px 0; border-top: 1px solid var(--line); }
  .footer-inner { display: flex; flex-direction: column; align-items: center; gap: 18px; }
  .social { display: flex; gap: 18px; }
  .social a {
    width: 40px; height: 40px; border-radius: 50%; display: grid; place-items: center;
    color: var(--muted); border: 1px solid var(--line);
    transition: color .15s ease, border-color .15s ease, transform .15s ease;
  }
  .social a:hover { color: var(--accent); border-color: var(--accent); transform: translateY(-2px); }
  .footer-meta { color: var(--muted); font-size: .9rem; }

  /* FAQ */
  .faq-section { padding: 0 0 80px; }
  .faq { max-width: 720px; margin: 0 auto; }
  .faq-item {
    border: 1px solid var(--line); border-radius: var(--radius);
    margin-bottom: 14px; overflow: hidden; transition: border-color .15s ease;
  }
  .faq-item[open] { border-color: var(--accent); }
  .faq-item summary {
    list-style: none; cursor: pointer;
    padding: 20px 22px; font-weight: 600; font-size: 1.02rem;
    display: flex; align-items: center; justify-content: space-between; gap: 16px;
  }
  .faq-item summary::-webkit-details-marker { display: none; }
  .faq-icon {
    flex: 0 0 18px; width: 18px; height: 18px; position: relative;
  }
  .faq-icon::before, .faq-icon::after {
    content: ""; position: absolute; background: var(--accent);
    transition: transform .2s ease;
  }
  .faq-icon::before { top: 8px; left: 0; width: 18px; height: 2px; }          /* horizontal */
  .faq-icon::after  { top: 0; left: 8px; width: 2px; height: 18px; }          /* vertical */
  .faq-item[open] .faq-icon::after { transform: scaleY(0); }                  /* hide vertical = minus */
  .faq-body {
    padding: 0 22px 20px; color: var(--muted); font-size: .98rem;
  }
  .faq-body p { margin: 0; }

  @media (max-width: 760px) {
    .nav-links { display: none; }
    .contact-grid { grid-template-columns: 1fr; gap: 36px; }
  }