:root {
  --accent: #3399f2;
  --accent-dark: #2570c2;
  --bg: #ffffff;
  --bg-tinted: #f6f8fb;
  --text: #0f1722;
  --muted: #5b6776;
  --line: #e6ebf2;
  --green: #2eba6b;
  --red: #f25264;
  --radius: 12px;
  --shadow-lg: 0 18px 60px rgba(15, 23, 34, 0.10);
  --shadow-md: 0 6px 18px rgba(15, 23, 34, 0.06);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font: 15px/1.6 -apple-system, BlinkMacSystemFont, "SF Pro Display", "Inter", system-ui, "Pretendard", sans-serif;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
code { font-family: "SF Mono", "JetBrains Mono", Menlo, monospace; font-size: 0.9em; background: var(--bg-tinted); padding: 1px 6px; border-radius: 4px; }
img { max-width: 100%; }

.container { max-width: 1120px; margin: 0 auto; padding: 0 22px; }
.container.narrow { max-width: 760px; }

.nav { position: sticky; top: 0; background: rgba(255,255,255,0.85); backdrop-filter: saturate(180%) blur(14px); border-bottom: 1px solid var(--line); z-index: 50; }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { display: flex; align-items: center; gap: 8px; color: var(--text); font-weight: 600; font-size: 17px; }
.brand:hover { text-decoration: none; }
.logo { width: 26px; height: 26px; border-radius: 6px; background: linear-gradient(135deg, var(--accent), var(--accent-dark)); display: inline-flex; align-items: center; justify-content: center; box-shadow: var(--shadow-md); }
.nav-links { display: flex; gap: 22px; align-items: center; }
.nav-links a { color: var(--muted); font-size: 14px; }
.nav-links a:hover { color: var(--text); text-decoration: none; }

.btn { display: inline-flex; align-items: center; justify-content: center; padding: 9px 18px; border-radius: 8px; font-weight: 600; font-size: 14px; transition: transform 0.05s ease, background 0.15s ease; user-select: none; }
.btn:hover { text-decoration: none; }
.btn-sm { padding: 6px 12px; font-size: 13px; }
.btn-primary { background: var(--accent); color: #fff !important; box-shadow: 0 2px 10px rgba(51,153,242,0.25); }
.btn-primary:hover { background: var(--accent-dark); }
.btn-ghost { background: var(--bg-tinted); color: var(--text) !important; border: 1px solid var(--line); }
.btn-ghost:hover { background: #eef2f7; }

.hero { padding: 80px 0 100px; background: radial-gradient(ellipse at 70% -20%, rgba(51,153,242,0.12), transparent 60%); }
.hero-grid { display: grid; grid-template-columns: 1fr 1.05fr; gap: 60px; align-items: center; }
.eyebrow { display: inline-block; font-size: 12px; font-weight: 600; color: var(--accent); background: rgba(51,153,242,0.12); padding: 4px 10px; border-radius: 999px; letter-spacing: 0.4px; }
.hero h1 { font-size: 52px; line-height: 1.05; margin: 18px 0 16px; letter-spacing: -0.02em; font-weight: 800; }
.hero h1 .grad { background: linear-gradient(135deg, var(--accent), #66b6ff); -webkit-background-clip: text; background-clip: text; color: transparent; }
.lead { font-size: 17px; color: var(--muted); max-width: 460px; }
.cta-row { display: flex; gap: 10px; margin-top: 26px; }
.meta { margin-top: 18px; font-size: 13px; color: var(--muted); }
.meta .dot { display: inline-block; width: 4px; height: 4px; background: var(--muted); border-radius: 50%; vertical-align: middle; margin: 0 6px; }

/* Demo card */
.demo-card { background: #ffffff; border-radius: 14px; box-shadow: var(--shadow-lg); border: 1px solid var(--line); overflow: hidden; }
.demo-header { display: flex; align-items: center; gap: 6px; padding: 10px 14px; background: #f9fafc; border-bottom: 1px solid var(--line); }
.demo-header > span:first-child { margin-right: 4px; }
.dot-red, .dot-amber, .dot-green { width: 11px; height: 11px; border-radius: 50%; display: inline-block; }
.dot-red { background: #ff5f57; }
.dot-amber { background: #febc2e; }
.dot-green { background: #28c840; }
.demo-title { margin-left: 8px; font-size: 12px; font-weight: 600; color: var(--muted); }
.demo-body { display: grid; grid-template-columns: 160px 1fr; min-height: 340px; }
.demo-sidebar { background: #fafbfd; border-right: 1px solid var(--line); padding: 10px 8px; }
.demo-sidebar .row { display: flex; align-items: center; gap: 8px; padding: 8px 10px; border-radius: 7px; font-size: 12.5px; font-weight: 500; color: var(--text); }
.demo-sidebar .row.active { background: rgba(51,153,242,0.14); }
.demo-sidebar .row small { margin-left: auto; font-size: 10px; font-family: "SF Mono", monospace; color: var(--muted); font-weight: 400; }
.demo-sidebar .status { width: 8px; height: 8px; border-radius: 50%; background: var(--green); display: inline-block; box-shadow: 0 0 0 4px rgba(46,186,107,0.18); }
.demo-sidebar .status.off { background: var(--red); box-shadow: 0 0 0 4px rgba(242,82,100,0.18); }

.demo-drop { position: relative; padding: 22px; display: flex; align-items: center; justify-content: center; overflow: hidden; }
.drop-target { width: 100%; max-width: 260px; padding: 26px 18px; border: 2px dashed rgba(51,153,242,0.4); border-radius: 14px; text-align: center; background: linear-gradient(180deg, rgba(51,153,242,0.06), rgba(51,153,242,0.01)); animation: pulseBorder 4.2s ease-in-out infinite; }
.drop-icon { width: 56px; height: 56px; border-radius: 50%; background: linear-gradient(135deg, var(--accent), var(--accent-dark)); margin: 0 auto 12px; display: flex; align-items: center; justify-content: center; box-shadow: 0 8px 20px rgba(51,153,242,0.35); }
.drop-text { font-weight: 600; margin-bottom: 4px; }
.drop-meta { font-size: 11px; color: var(--muted); font-family: "SF Mono", monospace; }

.ghost-file { position: absolute; top: 32px; padding: 6px 10px; background: #fff; border: 1px solid var(--line); border-radius: 6px; box-shadow: var(--shadow-md); font-size: 12px; font-weight: 500; pointer-events: none; }
#g1 { left: -50px; animation: flyDrop 4.2s ease-in-out infinite; }
#g2 { left: -50px; animation: flyDrop 4.2s ease-in-out infinite 1.4s; }

.status-toast { position: absolute; bottom: 18px; left: 50%; transform: translateX(-50%) translateY(20px); padding: 6px 14px; background: var(--green); color: #fff; font-size: 12px; font-weight: 600; border-radius: 999px; opacity: 0; animation: toastFlash 4.2s ease-in-out infinite 2.8s; }

@keyframes pulseBorder {
  0%, 100% { border-color: rgba(51,153,242,0.4); }
  50% { border-color: rgba(51,153,242,0.85); box-shadow: 0 0 0 6px rgba(51,153,242,0.08); }
}
@keyframes flyDrop {
  0%   { left: -50px; top: 32px; opacity: 0; }
  15%  { opacity: 1; }
  45%  { left: 50%; top: 130px; transform: translate(-50%, 0); opacity: 1; }
  55%  { left: 50%; top: 130px; transform: translate(-50%, 0); opacity: 0.2; }
  100% { left: 50%; top: 130px; transform: translate(-50%, 0); opacity: 0; }
}
@keyframes toastFlash {
  0%, 20% { opacity: 0; transform: translateX(-50%) translateY(20px); }
  30%, 70% { opacity: 1; transform: translateX(-50%) translateY(0); }
  85%, 100% { opacity: 0; transform: translateX(-50%) translateY(-10px); }
}

/* Sections */
.band { padding: 80px 0; }
.band-tinted { background: var(--bg-tinted); }
.band h2 { font-size: 36px; letter-spacing: -0.01em; margin: 0 0 12px; }
.section-lead { font-size: 17px; color: var(--muted); max-width: 600px; margin: 0 0 40px; }

.features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.feature { background: #fff; padding: 24px; border: 1px solid var(--line); border-radius: 12px; box-shadow: var(--shadow-md); }
.feat-ico { width: 38px; height: 38px; border-radius: 9px; background: rgba(51,153,242,0.12); color: var(--accent); display: flex; align-items: center; justify-content: center; margin-bottom: 14px; }
.feature h3 { font-size: 16px; margin: 0 0 6px; }
.feature p { font-size: 14px; color: var(--muted); margin: 0; }

.protocols { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.proto { background: #fff; padding: 22px; border-radius: 12px; border: 1px solid var(--line); position: relative; }
.proto.featured { border-color: var(--accent); box-shadow: 0 4px 18px rgba(51,153,242,0.18); }
.proto h4 { font-size: 18px; margin: 0 0 6px; font-weight: 700; }
.proto p { font-size: 13.5px; color: var(--muted); margin: 0; }
.badge { position: absolute; top: 14px; right: 14px; padding: 3px 8px; background: var(--accent); color: #fff; font-size: 10px; font-weight: 600; border-radius: 999px; letter-spacing: 0.3px; }

/* FAQ */
details { padding: 18px 0; border-bottom: 1px solid var(--line); }
summary { cursor: pointer; font-weight: 600; font-size: 16px; padding: 4px 0; outline: none; }
summary::-webkit-details-marker { display: none; }
summary::after { content: '＋'; float: right; color: var(--muted); transition: transform 0.15s ease; }
details[open] summary::after { transform: rotate(45deg); }
details p { margin: 10px 0 0; color: var(--muted); font-size: 15px; }

/* Download */
.dl-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 30px; }
.dl-card { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 26px; text-align: center; box-shadow: var(--shadow-md); }
.dl-card h3 { margin: 0 0 8px; font-size: 18px; }
.dl-card p { color: var(--muted); font-size: 14px; margin: 0 0 16px; }
.dl-card .btn { margin-top: auto; }

/* Footer */
.footer { background: #0f1722; color: #b3becd; padding: 60px 0 30px; }
.footer a { color: #d5dde6; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 30px; }
.footer strong { color: #fff; display: block; margin-bottom: 10px; font-size: 13px; letter-spacing: 0.6px; text-transform: uppercase; }
.footer ul { list-style: none; padding: 0; margin: 0; }
.footer ul li { margin: 6px 0; font-size: 14px; }
.footer .muted { color: #7c8896; margin-top: 6px; }
.copyright { margin-top: 40px; padding-top: 20px; border-top: 1px solid #1d2735; font-size: 12px; color: #5d6877; }

@media (max-width: 880px) {
  .hero { padding: 50px 0 70px; }
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .hero h1 { font-size: 38px; }
  .features, .protocols, .dl-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 600px) {
  .nav-links a:not(.btn) { display: none; }
  .features, .protocols, .dl-grid, .footer-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 32px; }
  .band h2 { font-size: 26px; }
  .band { padding: 50px 0; }
}