/* ============================================================
   BKterm — landing page
   Aesthetic: Apple-style. Light, airy, huge centred headlines,
   generous whitespace, the dark app windows as the "product
   shots". Restrained colour; brand green used sparingly.
   ============================================================ */

:root{
  --bg:       #ffffff;
  --tint:     #f5f5f7;   /* Apple grey tile */
  --dark:     #0a0c0f;   /* dark drama section + window chrome */
  --ink:      #1d1d1f;   /* near-black text */
  --ink-2:    #6e6e73;   /* secondary */
  --ink-3:    #86868b;   /* tertiary / captions */
  --line:     #d2d2d7;
  --line-2:   #e3e3e7;

  --brand:    #17a24a;   /* readable green on white (text / links) */
  --brand-2:  #34c759;   /* brighter green (fills, dots) */
  --brand-ink:#ffffff;

  /* window mockup palette (dark) */
  --w-bg:   #0e1116;
  --w-bg2:  #12161c;
  --w-panel:#161b22;
  --w-line: #232a33;
  --w-line2:#2d3742;
  --w-ink:  #dfe5ec;
  --w-dim:  #8b96a3;
  --w-mut:  #5c6672;
  --g:  #4ec972; --b:#4c9ffe; --a:#e0a44a; --v:#b586f0; --r:#f0605f;

  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
          "Helvetica Neue", "Noto Sans TC", "Segoe UI", Arial, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", "Cascadia Code", Consolas, monospace;

  --wrap: 1000px;
  --wrap-wide: 1120px;
}

*{box-sizing:border-box; margin:0; padding:0}
html{scroll-behavior:smooth}
body{
  background:var(--bg); color:var(--ink);
  font-family:var(--sans); font-size:17px; line-height:1.5;
  -webkit-font-smoothing:antialiased; text-rendering:optimizeLegibility;
  overflow-x:hidden;
}
a{color:inherit; text-decoration:none}
code{font-family:var(--mono); font-size:.86em; color:var(--brand);
  background:rgba(23,162,74,.08); padding:.08em .35em; border-radius:4px}
kbd{font-family:var(--mono); font-size:.8em; background:rgba(255,255,255,.08);
  border:1px solid var(--w-line2); border-radius:4px; padding:.05em .38em; color:var(--w-ink)}
.accent{color:var(--brand)}
.wrap{max-width:var(--wrap); margin:0 auto; padding:0 22px}

/* ---------- buttons / links ---------- */
.btn{display:inline-flex; align-items:center; justify-content:center; gap:.4em;
  font-family:var(--sans); font-size:1rem; font-weight:500; line-height:1;
  padding:.72em 1.35em; border-radius:980px; border:1px solid transparent;
  cursor:pointer; transition:.2s ease; white-space:nowrap}
.btn-primary{background:var(--brand); color:var(--brand-ink)}
.btn-primary:hover{background:#128a3d}
.btn-ghost{border-color:var(--line); color:var(--ink); background:transparent}
.btn-ghost:hover{background:var(--tint)}
.btn-sm{padding:.5em 1.05em; font-size:.9rem}
.btn-lg{padding:.9em 1.7em; font-size:1.06rem}
.btn-block{width:100%}
.link-more{color:var(--brand); font-size:1.02rem; font-weight:500; display:inline-flex;
  align-items:center; transition:.15s}
.link-more:hover{opacity:.7}

/* ============================================================
   NAV — thin, translucent, Apple menu bar
   ============================================================ */
.nav{position:sticky; top:0; z-index:50; height:52px;
  background:rgba(255,255,255,.72); backdrop-filter:saturate(180%) blur(20px);
  border-bottom:1px solid var(--line-2)}
.nav-inner{display:flex; align-items:center; gap:26px; height:52px; max-width:var(--wrap-wide)}
.brand{display:flex; align-items:center; gap:9px}
.brand-mark{display:inline-flex; gap:4px}
.brand-mark i{width:7px; height:7px; border-radius:50%; display:block}
.brand-mark i:nth-child(1){background:var(--brand-2)}
.brand-mark i:nth-child(2){background:var(--b)}
.brand-mark i:nth-child(3){background:var(--a)}
.brand-name{font-size:1.16rem; font-weight:600; letter-spacing:-.02em}
.nav-links{display:flex; gap:2px; margin:0 auto; font-size:.86rem}
.nav-links a{padding:.5em .8em; border-radius:7px; color:var(--ink-2); transition:.15s; font-weight:400}
.nav-links a:hover{color:var(--ink)}
.nav-right{display:flex; align-items:center; gap:14px; margin-left:auto}
.lang{display:inline-flex; border:1px solid var(--line); border-radius:980px; overflow:hidden}
.lang button{background:transparent; border:none; color:var(--ink-2); cursor:pointer;
  font-family:var(--sans); font-size:.78rem; padding:.35em .8em; transition:.15s}
.lang button + button{border-left:1px solid var(--line)}
.lang button:hover{color:var(--ink)}
.lang button.active{background:var(--ink); color:#fff}
.nav-burger{display:none; background:none; border:none; color:var(--ink); font-size:1.4rem; cursor:pointer}

/* ============================================================
   HERO — centred, huge headline, product shot below
   ============================================================ */
.hero{padding:78px 0 20px; text-align:center}
.hero-copy{max-width:820px}
.eyebrow{color:var(--brand); font-size:1.24rem; font-weight:600; letter-spacing:-.01em;
  margin-bottom:6px}
.hero h1{font-size:clamp(2.6rem,6.4vw,4.6rem); line-height:1.05; letter-spacing:-.035em;
  font-weight:600; margin-bottom:20px}
.lede{font-size:clamp(1.15rem,2.1vw,1.5rem); line-height:1.4; color:var(--ink-2);
  font-weight:400; max-width:38ch; margin:0 auto 30px}
.hero-actions{display:flex; gap:22px; align-items:center; justify-content:center; flex-wrap:wrap}

.hero-stage{margin-top:60px; max-width:var(--wrap-wide)}
.stat-row{display:flex; justify-content:center; gap:0; margin:60px auto 0; max-width:900px;
  flex-wrap:wrap}
.stat{flex:1; min-width:130px; padding:14px 18px; text-align:center; position:relative}
.stat + .stat::before{content:""; position:absolute; left:0; top:20%; height:60%; width:1px;
  background:var(--line)}
.stat b{display:block; font-size:1.9rem; font-weight:600; letter-spacing:-.02em; color:var(--ink)}
.stat span{display:block; font-size:.82rem; color:var(--ink-3); margin-top:2px}

/* ---------- window chrome (shared, dark product shot) ---------- */
.win{background:var(--w-bg2); border:1px solid var(--w-line2); border-radius:14px;
  overflow:hidden; box-shadow:0 50px 100px -40px rgba(0,0,0,.45), 0 14px 40px -20px rgba(0,0,0,.25)}
.win-title{display:flex; align-items:center; gap:12px; padding:11px 15px;
  background:var(--w-panel); border-bottom:1px solid var(--w-line)}
.tl-dots{display:inline-flex; gap:7px}
.tl-dots i{width:11px; height:11px; border-radius:50%; display:block}
.tl-dots i:nth-child(1){background:#e05d52}
.tl-dots i:nth-child(2){background:#e0a44a}
.tl-dots i:nth-child(3){background:#4ec972}
.tl-text{font-family:var(--mono); font-size:.78rem; color:var(--w-dim); white-space:nowrap;
  overflow:hidden; text-overflow:ellipsis}

.win-body{display:grid; grid-template-columns:170px 1fr; min-height:340px}
.sidebar{background:var(--w-panel); border-right:1px solid var(--w-line); padding:12px 9px;
  font-family:var(--mono); font-size:.77rem}
.sb-item{display:flex; align-items:center; gap:9px; padding:7px 9px; border-radius:6px;
  color:var(--w-dim); white-space:nowrap; overflow:hidden}
.sb-item.active{background:var(--w-bg); color:var(--w-ink); box-shadow:inset 2px 0 0 var(--g)}
.sb-mark{width:16px; height:16px; border-radius:4px; display:inline-flex; align-items:center;
  justify-content:center; font-size:.66rem; font-weight:700; flex:none; color:#06120a}
.sb-mark.local{background:var(--g)}
.sb-mark.ssh{background:var(--b); color:#03122b}
.sb-mark.serial{background:var(--a); color:#1c1203}
.sb-mark.telnet{background:var(--v); color:#1a0b2b}

.term{display:flex; flex-direction:column; min-width:0}
.tabs{display:flex; gap:3px; padding:7px 9px 0; background:var(--w-bg2)}
.tab{font-family:var(--mono); font-size:.75rem; color:var(--w-mut);
  padding:6px 13px; border-radius:7px 7px 0 0; border:1px solid transparent; border-bottom:none}
.tab.active{background:var(--w-panel); color:var(--w-ink); border-color:var(--w-line)}
.screen{font-family:var(--mono); font-size:.82rem; line-height:1.7; padding:16px 18px;
  flex:1; overflow:hidden; color:var(--w-ink); background:var(--w-bg2)}
.c-prompt{color:var(--g)} .c-path{color:var(--b)} .c-cmd{color:var(--w-ink)}
.c-ok{color:var(--g)} .c-warn{color:var(--a)} .c-dim{color:var(--w-mut)} .c-hl{color:var(--b)}
.cursor{color:var(--g); animation:blink 1.1s steps(1) infinite}
@keyframes blink{50%{opacity:0}}
.statusbar{display:flex; align-items:center; font-family:var(--mono); font-size:.72rem;
  background:var(--w-panel); border-top:1px solid var(--w-line)}
.sb-seg{padding:7px 12px; color:var(--w-dim); border-right:1px solid var(--w-line)}
.sb-seg b{color:var(--w-ink)}
.sb-seg.on{background:var(--g); color:#04170c; font-weight:700}
.sb-seg.warn,.sb-seg.warn b{color:var(--a)}
.sb-seg.dim{color:var(--w-mut); border:none}
.sb-grow{flex:1}

/* ============================================================
   BLOCKS — big centred intros, lots of air
   ============================================================ */
.block{padding:110px 0; text-align:center}
.block-tint{background:var(--tint)}
.block-head{max-width:760px; margin:0 auto 60px}
.block-head h2{font-size:clamp(2rem,4.4vw,3.3rem); line-height:1.08; letter-spacing:-.03em;
  font-weight:600}
.sub{font-size:clamp(1.08rem,1.7vw,1.35rem); line-height:1.45; color:var(--ink-2);
  margin-top:18px; font-weight:400}
.block-head .sub{max-width:44ch; margin-left:auto; margin-right:auto}

/* ---------- 01 connect ---------- */
.conn-grid{display:grid; grid-template-columns:repeat(2,1fr); gap:20px; text-align:left}
.conn-card{background:var(--tint); border-radius:20px; padding:34px 32px; transition:.25s ease}
.block-tint .conn-card{background:#fff}
.conn-card:hover{transform:translateY(-3px); box-shadow:0 20px 40px -24px rgba(0,0,0,.25)}
.conn-badge{width:44px; height:44px; border-radius:12px; display:flex; align-items:center;
  justify-content:center; font-family:var(--mono); font-weight:700; font-size:1.2rem; margin-bottom:18px}
.conn-badge.local{background:rgba(23,162,74,.12); color:var(--brand)}
.conn-badge.ssh{background:rgba(76,159,254,.14); color:#2b7fe0}
.conn-badge.serial{background:rgba(224,164,74,.16); color:#b9862f}
.conn-badge.telnet{background:rgba(181,134,240,.16); color:#8a55d6}
.conn-card h3{font-size:1.3rem; font-weight:600; letter-spacing:-.01em; margin-bottom:8px}
.conn-card p{color:var(--ink-2); font-size:1rem; line-height:1.5}

/* ---------- 02 compare ---------- */
.compare-win{max-width:var(--wrap-wide); margin:0 auto}
.cmp-body{display:grid; grid-template-columns:1fr 34px 1fr; background:var(--w-bg2); text-align:left}
.cmp-col{min-width:0}
.cmp-head{font-family:var(--mono); font-size:.76rem; color:var(--w-dim); padding:10px 15px;
  background:var(--w-panel); border-bottom:1px solid var(--w-line); display:flex; align-items:center;
  gap:9px; white-space:nowrap; overflow:hidden}
.cmp-tag{font-size:.68rem; padding:.12em .55em; border-radius:5px; background:var(--w-bg);
  border:1px solid var(--w-line2); color:var(--w-mut)}
.cmp-tag.remote{color:var(--b); border-color:rgba(76,159,254,.4)}
.cmp-code{font-family:var(--mono); font-size:.8rem; line-height:1.75; padding:12px 0;
  overflow:hidden; color:var(--w-ink)}
.cmp-code .ln{display:inline-block; width:2.6em; color:var(--w-mut); text-align:right;
  padding-right:1em; user-select:none}
.cmp-code .del{background:rgba(240,96,95,.12)}
.cmp-code .add{background:rgba(78,201,114,.12)}
.cmp-code .chg{background:rgba(224,164,74,.12)}
.tok-del{background:rgba(240,96,95,.3); border-radius:3px; padding:0 2px}
.tok-add{background:rgba(78,201,114,.3); border-radius:3px; padding:0 2px}
.tok-chg{background:rgba(224,164,74,.32); border-radius:3px; padding:0 2px}
.cmp-gutter{background:var(--w-panel); border-left:1px solid var(--w-line);
  border-right:1px solid var(--w-line); display:flex; flex-direction:column; align-items:center;
  padding-top:48px; gap:36px}
.g-arrow{color:var(--g); font-family:var(--mono); font-size:.95rem; cursor:pointer; line-height:1.75}
.g-spacer{height:1.75em}
.cmp-foot{display:flex; align-items:center; gap:18px; font-family:var(--mono); font-size:.74rem;
  padding:10px 15px; background:var(--w-panel); border-top:1px solid var(--w-line);
  color:var(--w-dim); flex-wrap:wrap; text-align:left}
.cf-item{display:inline-flex; align-items:center; gap:7px}
.sw{width:10px; height:10px; border-radius:3px; display:inline-block}
.sw.del{background:var(--r)} .sw.add{background:var(--g)} .sw.chg{background:var(--a)}
.cf-hint{color:var(--w-mut)}
.cmp-notes{display:grid; grid-template-columns:repeat(3,1fr); gap:36px 40px;
  max-width:var(--wrap-wide); margin:64px auto 0; text-align:left}
.cmp-notes > div{color:var(--ink-2); font-size:1rem; line-height:1.5}
.cmp-notes b{display:block; color:var(--ink); font-weight:600; font-size:1.08rem; margin-bottom:6px;
  letter-spacing:-.01em}
.cmp-notes kbd{background:var(--tint); border-color:var(--line); color:var(--ink)}
.block-tint .cmp-notes kbd{background:#fff}

/* ---------- 03 power ---------- */
.feat-grid{display:grid; grid-template-columns:repeat(3,1fr); gap:20px; text-align:left}
.feat{background:var(--tint); border-radius:20px; padding:30px 30px; transition:.25s ease}
.feat:hover{transform:translateY(-3px); box-shadow:0 20px 40px -24px rgba(0,0,0,.22)}
.f-kbd{font-family:var(--mono); font-size:.74rem; color:var(--brand);
  background:rgba(23,162,74,.1); padding:.2em .6em; border-radius:6px; display:inline-block;
  margin-bottom:16px}
.feat h4{font-size:1.2rem; font-weight:600; letter-spacing:-.01em; margin-bottom:7px}
.feat p{color:var(--ink-2); font-size:.98rem; line-height:1.5}

/* ---------- 04 engine (dark drama) ---------- */
.block-dark{background:var(--dark); color:#f5f5f7; text-align:left}
.kernel-inner{display:grid; grid-template-columns:1.25fr .9fr; gap:64px; align-items:center;
  max-width:var(--wrap-wide)}
.block-dark h2{font-size:clamp(2rem,4.2vw,3.1rem); line-height:1.08; letter-spacing:-.03em;
  font-weight:600; color:#fff}
.block-dark .sub{color:#a1a1a6; max-width:46ch; margin-left:0; margin-right:0}
.kernel-list{list-style:none; margin-top:34px; display:flex; flex-direction:column; gap:18px}
.kernel-list li{display:flex; gap:15px; color:#c7c7cc; font-size:1.02rem; align-items:baseline}
.kl-tag{font-family:var(--mono); font-size:.7rem; color:#7fd3ff; border:1px solid #2d3742;
  border-radius:6px; padding:.2em .55em; flex:none; min-width:78px; text-align:center;
  background:rgba(255,255,255,.03)}
.kernel-readout{background:#12161c; border:1px solid #232a33; border-radius:16px;
  padding:28px; font-family:var(--mono)}
.ro-title{font-size:.76rem; color:var(--w-mut); margin-bottom:18px}
.ro-row{display:flex; justify-content:space-between; align-items:baseline; padding:12px 0;
  border-bottom:1px solid #232a33; font-size:.9rem; color:#a1a1a6}
.ro-row b{color:var(--g); font-size:1.05rem}
.ro-bar{height:6px; background:#232a33; border-radius:3px; margin:20px 0 12px; overflow:hidden}
.ro-bar i{display:block; height:100%; background:linear-gradient(90deg,var(--g),#8ee6a5)}
.ro-note{font-size:.74rem; color:var(--w-mut); line-height:1.55}

/* ---------- 05 table ---------- */
.table-wrap{max-width:900px; margin:0 auto; background:#fff; border-radius:18px;
  border:1px solid var(--line-2); overflow:hidden; box-shadow:0 20px 50px -34px rgba(0,0,0,.2)}
.cmp-table{width:100%; border-collapse:collapse; font-size:.98rem; text-align:left}
.cmp-table th,.cmp-table td{padding:17px 20px; border-bottom:1px solid var(--line-2)}
.cmp-table thead th{font-size:.86rem; color:var(--ink-2); font-weight:500; background:var(--tint)}
.cmp-table td:first-child{color:var(--ink); font-weight:400}
.cmp-table th:not(:first-child),.cmp-table td:not(:first-child){text-align:center; width:15%}
.cmp-table tbody tr:last-child td{border-bottom:none}
th.col-us{color:var(--brand)!important; font-weight:700}
td.col-us{background:rgba(23,162,74,.05)}
.cmp-table .yes{color:var(--brand); font-weight:600; font-size:.9rem}
.cmp-table .mid{color:#b9862f; font-size:.9rem}
.cmp-table .no{color:var(--ink-3); font-size:.9rem}
.cmp-table .na{color:var(--line)}

/* ---------- download ---------- */
.block-download{background:var(--tint)}
.dl-inner h2{font-size:clamp(2rem,4.4vw,3.3rem); letter-spacing:-.03em; font-weight:600}
.dl-inner .sub{max-width:46ch; margin-left:auto; margin-right:auto}
.dl-actions{display:flex; gap:22px; justify-content:center; align-items:center; margin:30px 0 12px;
  flex-wrap:wrap}
.dl-hash{font-family:var(--mono); font-size:.78rem; color:var(--ink-3)}
.editions{display:grid; grid-template-columns:repeat(3,1fr); gap:20px; margin-top:64px; text-align:left}
.edition{background:#fff; border:1px solid var(--line-2); border-radius:20px; padding:32px 28px;
  display:flex; flex-direction:column}
.edition.featured{border-color:rgba(23,162,74,.5); box-shadow:0 24px 50px -30px rgba(23,162,74,.35)}
.ed-name{font-size:1.05rem; color:var(--ink-2); font-weight:500; display:flex; align-items:center; gap:9px}
.ed-tag{font-size:.68rem; background:var(--brand); color:#fff; padding:.15em .6em; border-radius:980px;
  font-weight:600}
.ed-price{font-size:2.2rem; font-weight:600; letter-spacing:-.02em; margin:12px 0 22px}
.ed-per{font-size:.9rem; color:var(--ink-3); font-weight:400}
.edition ul{list-style:none; display:flex; flex-direction:column; gap:13px; margin-bottom:28px; flex:1}
.edition li{color:var(--ink-2); font-size:.98rem; padding-left:26px; position:relative}
.edition li::before{content:"✓"; position:absolute; left:0; color:var(--brand); font-weight:700}

/* ---------- footer ---------- */
.footer{padding:56px 0 34px; background:#fff; border-top:1px solid var(--line-2)}
.footer-inner{display:grid; grid-template-columns:1.3fr 2fr; gap:44px; padding-bottom:36px;
  border-bottom:1px solid var(--line-2); max-width:var(--wrap-wide)}
.foot-brand .brand-name{font-size:1.3rem; font-weight:600}
.foot-brand p{color:var(--ink-3); font-size:.92rem; margin-top:12px; line-height:1.5}
.foot-cols{display:grid; grid-template-columns:repeat(3,1fr); gap:24px}
.foot-col h5{font-size:.84rem; color:var(--ink); margin-bottom:14px; font-weight:600}
.foot-col a{display:block; color:var(--ink-2); font-size:.9rem; padding:5px 0; transition:.15s}
.foot-col a:hover{color:var(--brand)}
.foot-bottom{display:flex; justify-content:space-between; padding-top:22px; max-width:var(--wrap-wide);
  font-size:.8rem; color:var(--ink-3); flex-wrap:wrap; gap:10px}

/* ============================================================
   REVEAL ON SCROLL
   ============================================================ */
.reveal{opacity:0; transform:translateY(22px); transition:opacity .7s ease, transform .7s ease}
.reveal.in{opacity:1; transform:none}
@media(prefers-reduced-motion:reduce){
  .reveal{opacity:1; transform:none; transition:none}
  .cursor{animation:none} html{scroll-behavior:auto}
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media(max-width:900px){
  .nav-links{display:none; position:absolute; top:52px; left:0; right:0; flex-direction:column;
    gap:0; background:rgba(255,255,255,.96); backdrop-filter:blur(20px);
    border-bottom:1px solid var(--line); padding:8px; margin:0}
  .nav-links.open{display:flex}
  .nav-links a{padding:13px 15px; border-radius:8px}
  .nav-burger{display:block}
  .nav .btn-primary{display:none}
  .kernel-inner{grid-template-columns:1fr; gap:38px}
  .cmp-notes{grid-template-columns:1fr 1fr; gap:30px}
  .footer-inner{grid-template-columns:1fr; gap:30px}
}
@media(max-width:680px){
  body{font-size:16px}
  .block{padding:72px 0}
  .block-head{margin-bottom:44px}
  .conn-grid,.feat-grid,.editions,.cmp-notes{grid-template-columns:1fr}
  .cmp-body{grid-template-columns:1fr}
  .cmp-gutter{display:none}
  .win-body{grid-template-columns:1fr}
  .sidebar{display:none}
  .stat{flex:1 1 40%}
  .stat:nth-child(3)::before,.stat:nth-child(5)::before{display:none}
  .foot-cols{grid-template-columns:1fr 1fr}
  .hero-actions,.dl-actions{gap:16px}
}