/* ===========================================================
   Vibe Coding Implementation Day — Setup Handbook
   Theme: light + PropertyLab blue
   =========================================================== */

:root {
  /* Brand / blue palette */
  --brand:        #1f6feb;
  --brand-600:    #175fd0;
  --brand-700:    #124aa6;
  --brand-050:    #e9f1ff;
  --brand-100:    #d6e6ff;

  /* Neutrals */
  --bg:           #eef3fb;
  --surface:      #ffffff;
  --surface-2:    #f5f8fd;
  --ink:          #10233f;
  --ink-soft:     #4a5d7a;
  --ink-faint:    #7488a6;
  --border:       #dce6f4;
  --border-soft:  #e8eefa;

  /* Accents */
  --ok:           #12a66b;
  --ok-050:       #e5f7ef;
  --code-bg:      #0f2440;
  --code-ink:     #d7e6ff;

  /* Shape */
  --radius:       16px;
  --radius-sm:    10px;
  --shadow:       0 10px 30px rgba(20, 60, 120, .08);
  --shadow-sm:    0 4px 14px rgba(20, 60, 120, .07);

  --maxw:         920px;
  --font: "Segoe UI", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB",
          "Noto Sans CJK SC", system-ui, -apple-system, Roboto, Arial, sans-serif;
  --mono: "Cascadia Code", "SF Mono", "Consolas", "JetBrains Mono", ui-monospace, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 84px; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ---------- Bilingual + OS visibility toggles ---------- */
.lang-en .zh, .lang-zh .en { display: none !important; }
.os-win  .os-mac { display: none !important; }
.os-mac  .os-win { display: none !important; }
/* inline OS spans should flow inline when shown */
span.os { display: inline; }

/* =========================================================
   TOP BAR
   ========================================================= */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, .88);
  backdrop-filter: saturate(150%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.topbar-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 10px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.brand { display: inline-flex; align-items: center; }
.brand-logo { height: 34px; width: auto; display: block; }

.controls { display: flex; gap: 10px; flex-wrap: wrap; }
.seg {
  display: inline-flex;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px;
}
.seg-btn {
  border: 0;
  background: transparent;
  color: var(--ink-soft);
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 999px;
  cursor: pointer;
  transition: all .15s ease;
  white-space: nowrap;
}
.seg-btn:hover { color: var(--brand); }
.seg-btn.is-active {
  background: var(--brand);
  color: #fff;
  box-shadow: 0 2px 8px rgba(31, 111, 235, .35);
}

/* =========================================================
   HERO
   ========================================================= */
.hero {
  background:
    radial-gradient(1200px 400px at 80% -10%, rgba(255,255,255,.25), transparent 60%),
    linear-gradient(135deg, var(--brand-700) 0%, var(--brand) 55%, #3b8bff 100%);
  color: #fff;
  padding: 54px 20px 60px;
}
.hero-inner { max-width: var(--maxw); margin: 0 auto; }
.kicker {
  display: inline-block;
  text-transform: uppercase;
  letter-spacing: .16em;
  font-size: 12px;
  font-weight: 700;
  color: #cfe0ff;
  margin-bottom: 12px;
}
.hero-title {
  margin: 0 0 10px;
  font-size: clamp(30px, 6vw, 50px);
  line-height: 1.08;
  font-weight: 800;
  letter-spacing: -.02em;
}
.hero-sub {
  margin: 0 0 8px;
  font-size: clamp(17px, 2.4vw, 22px);
  font-weight: 600;
  color: #eaf1ff;
}
.hero-tag { margin: 0 0 22px; color: #d3e2ff; font-size: 16px; max-width: 620px; }

.hero-meta { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 22px; }
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(255, 255, 255, .16);
  border: 1px solid rgba(255, 255, 255, .28);
  color: #fff;
  padding: 6px 13px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
}
.hero-hint {
  background: rgba(255, 255, 255, .12);
  border: 1px solid rgba(255, 255, 255, .22);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  font-size: 14.5px;
  color: #eef4ff;
  max-width: 700px;
}
.hero-hint b { color: #fff; }

.stepnav { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 22px; }
.stepnav a {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  background: #fff;
  color: var(--brand-700);
  text-decoration: none;
  font-size: 13.5px;
  font-weight: 700;
  padding: 7px 13px;
  border-radius: 999px;
  box-shadow: var(--shadow-sm);
  transition: transform .12s ease, background .12s ease;
}
.stepnav a:hover { transform: translateY(-1px); background: var(--brand-050); }

/* =========================================================
   PROGRESS
   ========================================================= */
.progress-wrap {
  position: sticky;
  top: 55px;
  z-index: 40;
  background: rgba(238, 243, 251, .92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.progress-inner { max-width: var(--maxw); margin: 0 auto; padding: 12px 20px; }
.progress-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  font-weight: 700;
  color: var(--ink-soft);
  margin-bottom: 8px;
}
.progress-count { color: var(--brand); font-size: 14px; }
.progress-track {
  height: 8px;
  background: var(--brand-100);
  border-radius: 999px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--brand), #45a0ff);
  border-radius: 999px;
  transition: width .4s cubic-bezier(.2,.7,.2,1);
}

/* =========================================================
   LAYOUT + CARDS
   ========================================================= */
.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 28px 20px 60px;
  display: flex;
  flex-direction: column;
  gap: 22px;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 26px 26px 28px;
}
.card-title {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin: 0 0 16px;
  font-size: 21px;
  font-weight: 800;
  letter-spacing: -.01em;
}
.card-title .ico { font-size: 22px; }

/* ---------- Step header ---------- */
.step-head {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 6px;
}
.step-num {
  flex: 0 0 auto;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--brand);
  color: #fff;
  font-size: 22px;
  font-weight: 800;
  display: grid;
  place-items: center;
  box-shadow: 0 6px 16px rgba(31, 111, 235, .35);
}
.step-title {
  margin: 0;
  flex: 1 1 auto;
  font-size: 21px;
  font-weight: 800;
  letter-spacing: -.01em;
}
.step-title b { color: var(--brand); font-weight: 800; }

.done-toggle {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 13.5px;
  font-weight: 700;
  color: var(--ink-soft);
  cursor: pointer;
  user-select: none;
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface-2);
  transition: all .15s ease;
}
.done-toggle:hover { border-color: var(--brand); color: var(--brand); }
.step-check {
  width: 18px; height: 18px;
  accent-color: var(--ok);
  cursor: pointer;
  margin: 0;
}
/* step turns "done" */
.step.is-done { border-color: var(--ok); }
.step.is-done .step-num { background: var(--ok); box-shadow: 0 6px 16px rgba(18,166,107,.32); }
.step.is-done .done-toggle { background: var(--ok-050); border-color: var(--ok); color: var(--ok); }

.why {
  margin: 12px 0 18px;
  color: var(--ink-soft);
  font-size: 15.5px;
  padding-left: 58px;
}
.why b { color: var(--ink); }

/* ---------- Steps list ---------- */
.steps { margin: 0 0 14px; padding-left: 20px; }
.steps li { margin: 8px 0; color: var(--ink); }
.steps li b, .steps li strong { color: var(--brand-700); }

.checklist { list-style: none; margin: 0 0 6px; padding: 0; }
.checklist li { margin: 4px 0; }
.checklist label {
  display: flex;
  gap: 11px;
  align-items: flex-start;
  padding: 11px 13px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  cursor: pointer;
  transition: border-color .15s ease, background .15s ease;
}
.checklist label:hover { border-color: var(--brand-100); }
.checklist input { margin-top: 3px; }
.checklist b { color: var(--brand-700); }
.checklist .link-btn { margin: 10px 0 2px; }
.os .link-btn { margin: 6px 0 10px; }
.steps .link-btn { margin: 8px 0 6px; }
.substep-body .link-btn { margin: 8px 0 4px; }

/* ---------- Sub-steps (1.1, 1.2 … inside a step) ---------- */
.substeps { margin-top: 2px; }
.substep {
  display: flex;
  gap: 14px;
  padding: 16px 0;
  border-top: 1px solid var(--border-soft);
}
.substep:first-child { border-top: 0; padding-top: 4px; }
.substep-num {
  flex: 0 0 auto;
  align-self: flex-start;
  font-weight: 800;
  font-size: 13.5px;
  color: var(--brand-700);
  background: var(--brand-050);
  border: 1px solid var(--brand-100);
  border-radius: 999px;
  padding: 4px 12px;
  min-width: 46px;
  text-align: center;
}
.substep-body { flex: 1 1 auto; min-width: 0; }
.substep-title { margin: 3px 0 4px; font-size: 15.5px; color: var(--ink); }
.substep-title b { color: var(--brand-700); }
.substep-note { margin: 4px 0 6px; font-size: 14px; color: var(--ink-soft); line-height: 1.55; }
.substep-note b { color: var(--ink); }

/* small link button (e.g. sign up at claude.ai) */
.link-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--brand);
  color: #fff;
  text-decoration: none;
  font-size: 13.5px;
  font-weight: 700;
  padding: 8px 16px;
  border-radius: 999px;
  box-shadow: 0 4px 12px rgba(31, 111, 235, .28);
  transition: transform .12s ease, background .12s ease;
}
.link-btn:hover { transform: translateY(-1px); background: var(--brand-600); }

/* inline chip for values like a WiFi password */
.chip {
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 700;
  background: var(--brand-050);
  border: 1px solid var(--brand-100);
  color: var(--brand-700);
  padding: 1px 8px;
  border-radius: 6px;
  letter-spacing: .04em;
  white-space: nowrap;
}

.alt {
  margin: 14px 0 6px;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--ink-faint);
}
.alt b { color: var(--ink-soft); }

/* ---------- Command block ---------- */
.cmd {
  display: flex;
  align-items: stretch;
  gap: 0;
  background: var(--code-bg);
  border-radius: var(--radius-sm);
  margin: 8px 0;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.cmd code {
  flex: 1 1 auto;
  font-family: var(--mono);
  font-size: 13.5px;
  color: var(--code-ink);
  padding: 13px 16px;
  overflow-x: auto;
  white-space: nowrap;
  line-height: 1.5;
}
.cmd code::before { content: "$ "; color: #6fa8ff; }
.copy {
  flex: 0 0 auto;
  border: 0;
  border-left: 1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.06);
  color: #cfe0ff;
  font: inherit;
  font-size: 12.5px;
  font-weight: 700;
  padding: 0 16px;
  cursor: pointer;
  transition: background .15s ease, color .15s ease;
}
.copy:hover { background: var(--brand); color: #fff; }
.copy.copied { background: var(--ok); color: #fff; }

/* ---------- Note / callout ---------- */
.note {
  margin: 16px 0;
  padding: 14px 16px;
  background: var(--brand-050);
  border: 1px solid var(--brand-100);
  border-left: 4px solid var(--brand);
  border-radius: var(--radius-sm);
  font-size: 14.5px;
  color: var(--ink);
}
.note b { color: var(--brand-700); }

/* ---------- Verify block ---------- */
.verify {
  margin-top: 18px;
  padding: 16px 18px;
  background: var(--ok-050);
  border: 1px solid #bfe9d5;
  border-radius: var(--radius-sm);
}
.verify-head { font-weight: 800; color: var(--ok); margin-bottom: 6px; font-size: 15px; }
.verify p { margin: 4px 0 8px; font-size: 14.5px; color: var(--ink-soft); }

/* ---------- Embedded video (YouTube) ---------- */
.video-embed {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  margin: 16px 0;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  background: #000;
}
.video-embed iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

/* ---------- Media placeholders ---------- */
.media { margin: 14px 0; }
.media img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}
.ph {
  border: 2px dashed var(--brand-100);
  background:
    repeating-linear-gradient(-45deg, rgba(31,111,235,.03) 0 12px, transparent 12px 24px),
    var(--surface-2);
  border-radius: var(--radius-sm);
  padding: 22px 18px;
  text-align: center;
  color: var(--ink-soft);
}
.ph-ico { font-size: 30px; display: block; margin-bottom: 8px; }
.ph-type {
  display: inline-block;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--brand);
  background: var(--brand-050);
  border: 1px solid var(--brand-100);
  border-radius: 999px;
  padding: 3px 10px;
  margin-bottom: 8px;
}
.ph-note { font-size: 14px; font-weight: 600; color: var(--ink); margin-bottom: 8px; }
.ph-file {
  display: inline-block;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--ink-faint);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 3px 8px;
}

/* =========================================================
   STARTER KIT
   ========================================================= */
.kit {
  background:
    radial-gradient(600px 200px at 100% 0%, rgba(31,111,235,.06), transparent 70%),
    var(--surface);
  border: 1px solid var(--brand-100);
}
.kit-title { color: var(--brand-700); }
.kit-body { font-size: 16px; color: var(--ink); margin: 0 0 16px; }
.kit-body b { color: var(--brand-700); }

.stack { display: flex; flex-wrap: wrap; gap: 9px; margin-bottom: 18px; }
.stack-pill {
  font-weight: 700;
  font-size: 13.5px;
  color: var(--brand-700);
  background: var(--brand-050);
  border: 1px solid var(--brand-100);
  border-radius: 999px;
  padding: 7px 15px;
}
.kit-btn {
  display: inline-block;
  margin-top: 8px;
  background: var(--brand);
  color: #fff;
  text-decoration: none;
  font-weight: 700;
  font-size: 15px;
  padding: 13px 22px;
  border-radius: 999px;
  box-shadow: 0 8px 20px rgba(31,111,235,.3);
  transition: transform .12s ease, background .12s ease;
  cursor: pointer;
}
.kit-btn:hover { transform: translateY(-1px); background: var(--brand-600); }

/* ---------- Help ---------- */
.help { background: var(--surface-2); }
.help p { margin: 0; color: var(--ink-soft); font-size: 15px; }
.help b { color: var(--ink); }

/* =========================================================
   FOOTER
   ========================================================= */
.footer {
  text-align: center;
  padding: 40px 20px 54px;
  border-top: 1px solid var(--border);
  background: var(--surface);
}
.footer-logo { height: 30px; opacity: .9; margin-bottom: 12px; }
.footer-line { margin: 0 0 4px; font-weight: 700; color: var(--ink); }
.footer-small { margin: 0; color: var(--ink-faint); font-size: 14px; }

/* ---------- Back to top ---------- */
.to-top {
  position: fixed;
  right: 20px;
  bottom: 20px;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  border: 0;
  background: var(--brand);
  color: #fff;
  font-size: 20px;
  cursor: pointer;
  box-shadow: 0 8px 20px rgba(31,111,235,.4);
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
  transition: all .25s ease;
  z-index: 60;
}
.to-top.show { opacity: 1; transform: translateY(0); pointer-events: auto; }
.to-top:hover { background: var(--brand-600); }

/* =========================================================
   RESPONSIVE
   ========================================================= */
@media (max-width: 640px) {
  .topbar-inner { flex-direction: column; align-items: stretch; gap: 10px; }
  .controls { justify-content: center; }
  .hero { padding: 40px 18px 46px; }
  .card { padding: 22px 18px 24px; }
  .why { padding-left: 0; }
  .step-head { flex-wrap: wrap; }
  .done-toggle { order: 3; }
  .progress-wrap { top: 0; position: static; }
}

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