/* ===== Agent 入门教程 — 样式 ===== */

:root {
  --bg:        #0b0f1a;
  --bg-soft:   #121829;
  --bg-card:   #161d31;
  --bg-code:   #0d1322;
  --border:    #243049;
  --text:      #e6ebf5;
  --text-dim:  #9aa7c2;
  --text-mute: #66728f;
  --accent:    #5eead4;  /* teal */
  --accent2:   #a78bfa;  /* purple */
  --accent3:   #fbbf24;  /* amber */
  --green:     #4ade80;
  --red:       #f87171;
  --blue:      #60a5fa;
  --grad: linear-gradient(135deg, #5eead4 0%, #a78bfa 100%);
  --shadow: 0 10px 40px rgba(0,0,0,.45);
  --mono: "JetBrains Mono", "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Roboto, sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* ===== Background glow ===== */
body::before {
  content: "";
  position: fixed;
  top: -30%; left: 50%;
  width: 900px; height: 900px;
  transform: translateX(-50%);
  background: radial-gradient(circle, rgba(94,234,212,.10), transparent 60%);
  pointer-events: none; z-index: 0;
}

/* ===== Layout ===== */
.layout { display: flex; min-height: 100vh; position: relative; z-index: 1; }

/* ===== Sidebar ===== */
.sidebar {
  width: 290px;
  flex-shrink: 0;
  background: rgba(18,24,41,.7);
  backdrop-filter: blur(12px);
  border-right: 1px solid var(--border);
  height: 100vh;
  position: sticky;
  top: 0;
  overflow-y: auto;
  padding: 26px 0 40px;
}
.sidebar::-webkit-scrollbar { width: 8px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 8px; }

.brand {
  padding: 0 24px 22px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 14px;
  cursor: pointer;
}
.brand h1 {
  font-size: 19px;
  font-weight: 800;
  letter-spacing: -.3px;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.brand p { font-size: 12px; color: var(--text-mute); margin-top: 4px; }

.progress-wrap { padding: 0 24px 16px; }
.progress-bar { height: 6px; background: var(--bg-code); border-radius: 6px; overflow: hidden; }
.progress-fill { height: 100%; width: 0; background: var(--grad); transition: width .4s ease; border-radius: 6px; }
.progress-label { font-size: 11px; color: var(--text-mute); margin-top: 6px; }

.nav-group-title {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-mute);
  padding: 16px 24px 6px;
  font-weight: 700;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 9px 24px;
  cursor: pointer;
  color: var(--text-dim);
  font-size: 14px;
  border-left: 3px solid transparent;
  transition: all .15s ease;
}
.nav-item:hover { background: rgba(94,234,212,.06); color: var(--text); }
.nav-item.active {
  background: rgba(94,234,212,.10);
  border-left-color: var(--accent);
  color: var(--text);
  font-weight: 600;
}
.nav-num {
  width: 24px; height: 24px;
  flex-shrink: 0;
  border-radius: 7px;
  background: var(--bg-code);
  border: 1px solid var(--border);
  display: grid; place-items: center;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--text-mute);
}
.nav-item.active .nav-num { background: var(--grad); color: #0b0f1a; border-color: transparent; font-weight: 700; }
.nav-item.done .nav-num::after { content: "✓"; }
.nav-item.done .nav-num { color: var(--green); }

/* ===== Main ===== */
.main { flex: 1; min-width: 0; }
.content { max-width: 820px; margin: 0 auto; padding: 56px 40px 120px; }

/* ===== Hero (lesson 0) ===== */
.hero { text-align: center; padding: 30px 0 10px; }
.hero .eyebrow {
  display: inline-block;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--accent);
  border: 1px solid var(--border);
  border-radius: 30px;
  padding: 5px 16px;
  margin-bottom: 26px;
  background: rgba(94,234,212,.05);
}
.hero h1 {
  font-size: 46px;
  line-height: 1.18;
  font-weight: 800;
  letter-spacing: -1px;
  margin-bottom: 20px;
}
.hero h1 .g { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero .lead { font-size: 18px; color: var(--text-dim); max-width: 620px; margin: 0 auto 36px; }

.formula {
  font-family: var(--mono);
  font-size: 17px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px;
  margin: 30px 0;
  box-shadow: var(--shadow);
}
.formula .plus { color: var(--accent3); margin: 0 10px; }
.formula .model { color: var(--accent); }
.formula .harness { color: var(--accent2); }

.cta {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  background: var(--grad);
  color: #0b0f1a;
  font-weight: 700;
  font-size: 16px;
  padding: 14px 30px;
  border-radius: 12px;
  border: none;
  cursor: pointer;
  margin-top: 14px;
  transition: transform .15s ease, box-shadow .15s ease;
  box-shadow: 0 8px 24px rgba(94,234,212,.25);
}
.cta:hover { transform: translateY(-2px); box-shadow: 0 12px 30px rgba(94,234,212,.4); }

.hero-stats { display: flex; gap: 16px; justify-content: center; margin-top: 50px; flex-wrap: wrap; }
.hero-stat { background: var(--bg-card); border: 1px solid var(--border); border-radius: 12px; padding: 18px 26px; }
.hero-stat .n { font-size: 30px; font-weight: 800; background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero-stat .l { font-size: 12px; color: var(--text-mute); margin-top: 2px; }

/* ===== Lesson header ===== */
.lesson-meta { display: flex; align-items: center; gap: 12px; margin-bottom: 18px; }
.chip {
  font-family: var(--mono);
  font-size: 12px;
  padding: 4px 12px;
  border-radius: 20px;
  background: rgba(167,139,250,.12);
  color: var(--accent2);
  border: 1px solid rgba(167,139,250,.25);
}
.chip.stage { background: rgba(94,234,212,.10); color: var(--accent); border-color: rgba(94,234,212,.25); }

.lesson h1 { font-size: 34px; font-weight: 800; letter-spacing: -.6px; margin-bottom: 14px; line-height: 1.25; }

.aphorism {
  border-left: 3px solid var(--accent3);
  background: linear-gradient(90deg, rgba(251,191,36,.08), transparent);
  padding: 14px 20px;
  border-radius: 0 10px 10px 0;
  margin: 0 0 32px;
  font-size: 16px;
  color: var(--text);
}
.aphorism .q { color: var(--accent3); font-weight: 600; font-style: italic; }

/* ===== Content blocks ===== */
.lesson h2 {
  font-size: 22px;
  font-weight: 700;
  margin: 40px 0 14px;
  display: flex; align-items: center; gap: 10px;
}
.lesson h2 .ic { font-size: 20px; }
.lesson h3 { font-size: 17px; font-weight: 700; margin: 26px 0 10px; color: var(--accent); }
.lesson p { color: var(--text-dim); margin-bottom: 16px; font-size: 15.5px; }
.lesson p strong { color: var(--text); font-weight: 600; }
.lesson ul, .lesson ol { color: var(--text-dim); margin: 0 0 16px; padding-left: 24px; }
.lesson li { margin-bottom: 8px; font-size: 15.5px; }
.lesson li strong { color: var(--text); }
.lesson code:not(pre code) {
  font-family: var(--mono);
  font-size: 13px;
  background: var(--bg-code);
  border: 1px solid var(--border);
  padding: 2px 7px;
  border-radius: 6px;
  color: var(--accent);
}

/* analogy box */
.analogy {
  display: flex; gap: 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px 22px;
  margin: 24px 0;
}
.analogy .emoji { font-size: 30px; line-height: 1; }
.analogy .body h4 { font-size: 14px; color: var(--accent2); margin-bottom: 6px; text-transform: uppercase; letter-spacing: .5px; }
.analogy .body p { margin: 0; color: var(--text-dim); }

/* callout */
.callout {
  border-radius: 12px;
  padding: 16px 20px;
  margin: 22px 0;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  font-size: 15px;
  color: var(--text-dim);
}
.callout.key { border-color: rgba(74,222,128,.3); background: rgba(74,222,128,.06); }
.callout.key strong { color: var(--green); }
.callout.warn { border-color: rgba(248,113,113,.3); background: rgba(248,113,113,.06); }
.callout.warn strong { color: var(--red); }
.callout .t { display: block; font-weight: 700; margin-bottom: 4px; color: var(--text); }

/* ===== Code block ===== */
.code-block {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 12px;
  margin: 22px 0;
  overflow: hidden;
  box-shadow: var(--shadow);
}
.code-head {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 16px;
  background: rgba(255,255,255,.02);
  border-bottom: 1px solid var(--border);
}
.code-head .dot { width: 11px; height: 11px; border-radius: 50%; }
.code-head .dot.r { background: #ff5f56; }
.code-head .dot.y { background: #ffbd2e; }
.code-head .dot.g { background: #27c93f; }
.code-head .fname { font-family: var(--mono); font-size: 12px; color: var(--text-mute); margin-left: 8px; }
.code-block pre { padding: 18px 20px; overflow-x: auto; }
.code-block code { font-family: var(--mono); font-size: 13.5px; line-height: 1.7; color: #cdd6f4; white-space: pre; }
.code-block pre::-webkit-scrollbar { height: 8px; }
.code-block pre::-webkit-scrollbar-thumb { background: var(--border); border-radius: 8px; }

/* syntax highlight tokens */
.tok-kw { color: #c792ea; }
.tok-fn { color: #82aaff; }
.tok-str { color: #c3e88d; }
.tok-num { color: #f78c6c; }
.tok-com { color: #5c6a87; font-style: italic; }
.tok-builtin { color: #ffcb6b; }
.tok-op { color: #89ddff; }

/* ===== Loop Simulator ===== */
.sim {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  margin: 28px 0;
  box-shadow: var(--shadow);
}
.sim-title { font-size: 15px; font-weight: 700; margin-bottom: 4px; display: flex; align-items: center; gap: 8px; }
.sim-sub { font-size: 13px; color: var(--text-mute); margin-bottom: 20px; }

.sim-stage {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr;
  gap: 8px;
  align-items: center;
  margin-bottom: 20px;
}
.sim-node {
  text-align: center;
  padding: 16px 8px;
  border-radius: 12px;
  border: 2px solid var(--border);
  background: var(--bg-code);
  transition: all .3s ease;
  position: relative;
}
.sim-node .ne { font-size: 26px; }
.sim-node .nl { font-size: 12px; color: var(--text-dim); margin-top: 4px; font-weight: 600; }
.sim-node.active {
  border-color: var(--accent);
  background: rgba(94,234,212,.12);
  transform: scale(1.06);
  box-shadow: 0 0 24px rgba(94,234,212,.3);
}
.sim-node.active .nl { color: var(--accent); }
.sim-arrow { font-size: 20px; color: var(--text-mute); transition: color .3s; }
.sim-arrow.active { color: var(--accent); }

.sim-screen {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px;
  min-height: 140px;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.7;
  margin-bottom: 16px;
}
.sim-line { margin-bottom: 6px; opacity: 0; animation: fadeUp .4s ease forwards; }
.sim-line .role { display: inline-block; min-width: 78px; font-weight: 700; }
.sim-line .role.user { color: var(--blue); }
.sim-line .role.llm { color: var(--accent2); }
.sim-line .role.tool { color: var(--accent3); }
.sim-line .role.sys { color: var(--text-mute); }
.sim-line .txt { color: var(--text-dim); }
.sim-line .hl { color: var(--accent); }
@keyframes fadeUp { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }

.sim-controls { display: flex; gap: 10px; align-items: center; }
.sim-btn {
  background: var(--grad);
  color: #0b0f1a;
  border: none;
  font-weight: 700;
  padding: 10px 22px;
  border-radius: 9px;
  cursor: pointer;
  font-size: 14px;
  transition: transform .12s, opacity .2s;
}
.sim-btn:hover { transform: translateY(-1px); }
.sim-btn:disabled { opacity: .4; cursor: not-allowed; transform: none; }
.sim-btn.ghost { background: transparent; border: 1px solid var(--border); color: var(--text-dim); }
.sim-step-label { font-size: 13px; color: var(--text-mute); margin-left: auto; font-family: var(--mono); }

/* ===== Nav footer ===== */
.lesson-nav {
  display: flex; justify-content: space-between; gap: 16px;
  margin-top: 60px;
  padding-top: 30px;
  border-top: 1px solid var(--border);
}
.lesson-nav a {
  flex: 1;
  text-decoration: none;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 20px;
  transition: all .15s ease;
  cursor: pointer;
}
.lesson-nav a:hover { border-color: var(--accent); transform: translateY(-2px); }
.lesson-nav a.next { text-align: right; }
.lesson-nav .dir { font-size: 12px; color: var(--text-mute); }
.lesson-nav .ttl { font-size: 15px; font-weight: 700; color: var(--text); margin-top: 3px; }
.lesson-nav a.disabled { opacity: .3; pointer-events: none; }

/* ===== 杂项 ===== */
p.muted { color: var(--text-mute); font-size: 13.5px; }

/* 速查表（总结页两栏） */
.recap {
  display: grid; grid-template-columns: 1fr 1fr; gap: 22px;
  margin: 18px 0 8px;
}
.recap-col {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 14px; padding: 18px 20px;
}
.recap-col h4 {
  margin: 14px 0 8px; font-size: 14px; color: var(--accent);
  letter-spacing: .3px;
}
.recap-col h4:first-child { margin-top: 0; }
.recap-col ol { margin: 0 0 4px; padding-left: 22px; }
.recap-col li { margin: 4px 0; font-size: 14px; color: var(--text-dim); }

/* ===== Mobile ===== */
.menu-toggle {
  display: none;
  position: fixed; top: 16px; left: 16px; z-index: 50;
  background: var(--bg-card); border: 1px solid var(--border);
  color: var(--text); width: 44px; height: 44px; border-radius: 11px;
  font-size: 20px; cursor: pointer;
}
.overlay { display: none; }

@media (max-width: 920px) {
  .menu-toggle { display: block; }
  .sidebar {
    position: fixed; left: 0; top: 0; z-index: 60;
    transform: translateX(-100%); transition: transform .3s ease;
  }
  .sidebar.open { transform: translateX(0); }
  .overlay.show { display: block; position: fixed; inset: 0; background: rgba(0,0,0,.5); z-index: 55; }
  .content { padding: 70px 22px 100px; }
  .hero h1 { font-size: 32px; }
  .lesson h1 { font-size: 26px; }
  .sim-stage { grid-template-columns: 1fr; gap: 4px; }
  .sim-arrow { transform: rotate(90deg); }
  .recap { grid-template-columns: 1fr; gap: 14px; }
}