*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --bg: #ffffff;
  --bg-soft: #f7f7f8;
  --bg-subtle: #f0f0f2;
  --border: #e4e4e8;
  --border-strong: #c8c8d0;
  --text: #0f0f11;
  --text-2: #4a4a58;
  --text-3: #8a8a9a;
  --accent: #2563eb;
  --accent-soft: #eff4ff;
  --accent-mid: #bfcfff;
  --java: #e8821c;
  --js: #ca9a04;
  --py: #2563eb;
}
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; }

nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  height: 60px; padding: 0 40px;
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.logo {
  display: flex; align-items: center; gap: 8px;
  font-weight: 700; font-size: 15px; letter-spacing: -0.3px;
}
.logo-icon {
  width: 28px; height: 28px; background: var(--text);
  border-radius: 7px; display: flex; align-items: center; justify-content: center;
}
.logo-icon svg { width: 14px; height: 14px; fill: none; stroke: white; stroke-width: 2; stroke-linecap: round; }
.nav-links { display: flex; gap: 4px; }
.nav-links a {
  font-size: 13.5px; font-weight: 500; color: var(--text-2);
  padding: 6px 12px; border-radius: 7px; transition: background 0.15s, color 0.15s;
}
.nav-links a:hover { background: var(--bg-soft); color: var(--text); }
.nav-right { display: flex; align-items: center; gap: 10px; }
.badge-ver {
  font-size: 11.5px; font-weight: 600;
  font-family: 'JetBrains Mono', monospace;
  color: var(--text-3); background: var(--bg-soft);
  border: 1px solid var(--border); padding: 4px 10px; border-radius: 100px;
}
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  font-family: 'Inter', sans-serif; font-size: 13.5px; font-weight: 600;
  padding: 8px 18px; border-radius: 8px; border: none; cursor: pointer; transition: all 0.15s;
}
.btn-dark { background: var(--text); color: white; }
.btn-dark:hover { background: #2a2a35; }
.btn-outline { background: white; color: var(--text); border: 1px solid var(--border-strong); }
.btn-outline:hover { background: var(--bg-soft); }

.hero {
  padding: 130px 40px 90px; max-width: 1100px; margin: 0 auto;
}
.kicker {
  display: inline-flex; align-items: center; gap: 7px;
  font-size: 12px; font-weight: 600; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 24px;
}
.kicker-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--accent); }
.hero h1 {
  font-size: clamp(42px, 6vw, 72px); font-weight: 800;
  letter-spacing: -0.04em; line-height: 1.05;
  max-width: 700px; margin-bottom: 22px;
}
.hero h1 em { font-style: normal; color: var(--accent); }
.hero-sub {
  font-size: 17px; font-weight: 400; color: var(--text-2);
  max-width: 480px; line-height: 1.65; margin-bottom: 36px;
}
.hero-btns { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 56px; }
.hero-btns .btn { font-size: 14px; padding: 10px 22px; }
.lang-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.lang-chip {
  display: flex; align-items: center; gap: 7px;
  font-size: 13px; font-weight: 600; color: var(--text-2);
  background: var(--bg-soft); border: 1px solid var(--border);
  padding: 6px 14px; border-radius: 100px;
}
.lang-chip .dot { width: 8px; height: 8px; border-radius: 50%; }
.lang-chip.java .dot { background: var(--java); }
.lang-chip.js   .dot { background: var(--js); }
.lang-chip.py   .dot { background: var(--py); }
.lang-arr { font-size: 15px; color: var(--border-strong); }

.divider { border: none; border-top: 1px solid var(--border); }
.section { padding: 80px 40px; max-width: 1100px; margin: 0 auto; }
.sec-label {
  font-size: 11.5px; font-weight: 700; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--text-3); margin-bottom: 12px;
}
.sec-title {
  font-size: clamp(26px, 3.5vw, 38px); font-weight: 800;
  letter-spacing: -0.03em; line-height: 1.15; margin-bottom: 12px;
}
.sec-desc { font-size: 16px; color: var(--text-2); max-width: 460px; line-height: 1.65; }

.demo-box {
  margin-top: 40px; border: 1px solid var(--border);
  border-radius: 16px; overflow: hidden; background: var(--bg);
}
.demo-topbar {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px; background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
}
.traffic { display: flex; gap: 6px; }
.traffic span { width: 11px; height: 11px; border-radius: 50%; }
.traffic span:nth-child(1) { background: #ff5f57; }
.traffic span:nth-child(2) { background: #febc2e; }
.traffic span:nth-child(3) { background: #28c840; }
.demo-path { font-family: 'JetBrains Mono', monospace; font-size: 11.5px; color: var(--text-3); }
.demo-toolbar {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 14px; border-bottom: 1px solid var(--border);
}
.tbar-label { font-size: 11.5px; font-weight: 500; color: var(--text-3); }
select.ls {
  font-family: 'JetBrains Mono', monospace; font-size: 12px; font-weight: 500;
  color: var(--text); background: var(--bg-soft); border: 1px solid var(--border);
  padding: 5px 10px; border-radius: 7px; cursor: pointer; outline: none; transition: border-color 0.15s;
}
select.ls:focus { border-color: var(--accent); }
.run-btn {
  margin-left: auto; display: flex; align-items: center; gap: 7px;
  background: var(--text); color: white; border: none;
  font-family: 'Inter', sans-serif; font-size: 12.5px; font-weight: 600;
  padding: 7px 16px; border-radius: 7px; cursor: pointer; transition: background 0.15s, transform 0.1s;
}
.run-btn:hover { background: #2a2a35; }
.run-btn:active { transform: scale(0.98); }
.run-btn.busy { opacity: 0.6; pointer-events: none; }
.run-btn .spin {
  width: 12px; height: 12px; border: 1.5px solid rgba(255,255,255,0.3);
  border-top-color: white; border-radius: 50%;
  animation: spin 0.65s linear infinite; display: none;
}
.run-btn.busy .spin { display: block; }
.run-btn.busy .rl { display: none; }
@keyframes spin { to { transform: rotate(360deg); } }
.demo-split { display: grid; grid-template-columns: 1fr 1fr; }
.demo-pane { padding: 18px; }
.demo-pane:first-child { border-right: 1px solid var(--border); }
.pane-hd {
  display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px;
}
.plang {
  font-size: 11px; font-weight: 700; letter-spacing: 0.07em;
  text-transform: uppercase; padding: 3px 9px; border-radius: 5px;
}
.plang.java { background: #fff4e6; color: #b45309; }
.plang.js   { background: #fefce8; color: #92400e; }
.plang.py   { background: #eff4ff; color: #1e40af; }
.pane-hint { font-size: 11px; color: var(--text-3); }
textarea.code {
  width: 100%; min-height: 200px; background: transparent; border: none;
  resize: vertical; font-family: 'JetBrains Mono', monospace;
  font-size: 12.5px; color: var(--text); outline: none; line-height: 1.75;
}
.code-out {
  font-family: 'JetBrains Mono', monospace; font-size: 12.5px;
  color: var(--text); line-height: 1.75; white-space: pre-wrap; min-height: 200px;
}
.code-out.empty { color: var(--text-3); }
.copy-sm {
  font-size: 11px; font-weight: 600; color: var(--text-3);
  background: var(--bg-soft); border: 1px solid var(--border);
  padding: 3px 9px; border-radius: 5px; cursor: pointer; transition: color 0.15s;
}
.copy-sm:hover { color: var(--text); }

.feat-grid {
  margin-top: 40px; display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 1px; background: var(--border); border: 1px solid var(--border);
  border-radius: 16px; overflow: hidden;
}
.feat { background: var(--bg); padding: 28px 26px; transition: background 0.15s; }
.feat:hover { background: var(--bg-soft); }
.feat-num { font-size: 11px; font-weight: 700; font-family: 'JetBrains Mono', monospace; color: var(--text-3); margin-bottom: 16px; }
.feat h3 { font-size: 15px; font-weight: 700; letter-spacing: -0.02em; margin-bottom: 8px; }
.feat p { font-size: 13.5px; color: var(--text-2); line-height: 1.6; }

.cmds {
  margin-top: 40px; display: flex; flex-direction: column;
  border: 1px solid var(--border); border-radius: 16px; overflow: hidden;
}
.cmd-row {
  display: grid; grid-template-columns: 2fr 80px 1fr;
  align-items: center; gap: 16px; padding: 16px 22px;
  border-bottom: 1px solid var(--border); transition: background 0.15s;
}
.cmd-row:last-child { border-bottom: none; }
.cmd-row:hover { background: var(--bg-soft); }
.cmd-code { font-family: 'JetBrains Mono', monospace; font-size: 13px; }
.cmd-code .arg { color: var(--text-3); }
.cmd-tag {
  font-size: 11px; font-weight: 600; color: var(--accent);
  background: var(--accent-soft); border: 1px solid var(--accent-mid);
  padding: 3px 10px; border-radius: 100px; text-align: center; white-space: nowrap;
}
.cmd-desc { font-size: 13px; color: var(--text-2); }

.install-wrap { margin-top: 40px; display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.icard { background: var(--bg-soft); border: 1px solid var(--border); border-radius: 16px; overflow: hidden; }
.icard-hd {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 16px; border-bottom: 1px solid var(--border); background: white;
}
.icard-title { font-size: 12.5px; font-weight: 600; color: var(--text-2); }
pre.icode {
  padding: 18px; font-family: 'JetBrains Mono', monospace;
  font-size: 12px; line-height: 1.8; color: var(--text); overflow-x: auto;
}
pre.icode .c  { color: var(--text-3); }
pre.icode .kw { color: var(--accent); }

.tree-box {
  margin-top: 20px; background: var(--bg-soft); border: 1px solid var(--border);
  border-radius: 16px; padding: 22px 24px;
  font-family: 'JetBrains Mono', monospace; font-size: 12.5px; line-height: 2;
}
.tree-box .root { font-weight: 700; }
.tree-box .dir  { color: var(--java); }
.tree-box .note { color: var(--text-3); }

footer { border-top: 1px solid var(--border); padding: 28px 40px; }
.footer-inner {
  max-width: 1100px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 12px;
}
.footer-logo { font-weight: 700; font-size: 14px; letter-spacing: -0.3px; }
.footer-meta { font-size: 12.5px; color: var(--text-3); display: flex; gap: 24px; flex-wrap: wrap; }

#toast {
  position: fixed; bottom: 24px; right: 24px;
  background: var(--text); color: white; font-size: 13px; font-weight: 500;
  padding: 10px 16px; border-radius: 9px;
  opacity: 0; transform: translateY(8px); transition: all 0.25s;
  pointer-events: none; z-index: 999;
}
#toast.show { opacity: 1; transform: translateY(0); }

.reveal { opacity: 0; transform: translateY(16px); transition: opacity 0.5s ease, transform 0.5s ease; }
.reveal.in { opacity: 1; transform: translateY(0); }

@media (max-width: 720px) {
  nav { padding: 0 20px; }
  .nav-links { display: none; }
  .hero, .section { padding-left: 20px; padding-right: 20px; }
  .demo-split { grid-template-columns: 1fr; }
  .demo-pane:first-child { border-right: none; border-bottom: 1px solid var(--border); }
  .feat-grid { grid-template-columns: 1fr; }
  .cmd-row { grid-template-columns: 1fr; gap: 4px; }
  .install-wrap { grid-template-columns: 1fr; }
  footer { padding: 24px 20px; }
}