/* ============================================================
   NexBuild OS-Agent — Monochrome Design System
   黑白高级风格：纸墨对比、发丝线、衬线斜体点睛、大面积留白
   ============================================================ */

:root {
  --bg: #0a0a0a;            /* 墨黑 */
  --ink: #f4f3ee;           /* 暖白 */
  --muted: #9a9a94;         /* 灰 */
  --faint: #5c5c58;         /* 弱灰 */
  --line: rgba(244, 243, 238, 0.14);
  --line-strong: rgba(244, 243, 238, 0.32);
  --paper: #f4f3ee;         /* 反白纸面 */
  --paper-ink: #0a0a0a;
  --paper-line: rgba(10, 10, 10, 0.16);
  --font-sans: "Space Grotesk", "PingFang SC", "Noto Sans SC", sans-serif;
  --font-serif: "Fraunces", "Songti SC", "Noto Serif SC", serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", monospace;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-weight: 400;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

::selection { background: var(--ink); color: var(--bg); }

::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: #2a2a28; border: 2px solid var(--bg); }
::-webkit-scrollbar-thumb:hover { background: #3d3d3a; }

.mono { font-family: var(--font-mono); }

.serif-italic {
  font-family: var(--font-serif);
  font-style: italic;
  font-weight: 480;
  font-variation-settings: "opsz" 144;
}

/* ---------- 滚动进度线 ---------- */
.progress-line {
  position: fixed; top: 0; left: 0; z-index: 200;
  height: 2px; width: 100%;
  background: var(--ink);
  transform-origin: 0 50%;
  transform: scaleX(0);
}

/* ---------- 自定义光标 ---------- */
.cursor-dot, .cursor-ring {
  position: fixed; top: 0; left: 0; z-index: 300;
  pointer-events: none; border-radius: 50%;
  transform: translate(-50%, -50%);
  display: none;
}
.cursor-dot { width: 6px; height: 6px; background: var(--ink); }
.cursor-ring {
  width: 34px; height: 34px;
  border: 1px solid var(--line-strong);
  transition: width 0.3s var(--ease), height 0.3s var(--ease), border-color 0.3s;
}
.cursor-ring.is-hover { width: 56px; height: 56px; border-color: var(--ink); }
@media (pointer: fine) {
  .cursor-dot, .cursor-ring { display: block; }
}

/* ---------- 导航 ---------- */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px clamp(20px, 4vw, 56px);
  border-bottom: 1px solid transparent;
  transition: background 0.4s, border-color 0.4s, padding 0.4s;
}
.nav.is-scrolled {
  background: rgba(10, 10, 10, 0.82);
  backdrop-filter: blur(14px);
  border-bottom-color: var(--line);
  padding-top: 12px; padding-bottom: 12px;
}
.nav-brand { display: flex; align-items: center; gap: 12px; text-decoration: none; color: var(--ink); }
.nav-mark { width: 26px; height: 26px; }
.nav-word { font-weight: 700; letter-spacing: 0.14em; font-size: 15px; }
.nav-word em {
  display: block; font-style: normal; font-family: var(--font-mono);
  font-size: 8px; letter-spacing: 0.42em; color: var(--muted); margin-top: 1px;
}
.nav-links { display: flex; gap: clamp(14px, 2.4vw, 34px); }
.nav-links a {
  color: var(--muted); text-decoration: none; font-size: 13px;
  letter-spacing: 0.08em; position: relative; transition: color 0.3s;
}
.nav-links a::after {
  content: ""; position: absolute; left: 0; bottom: -4px;
  width: 100%; height: 1px; background: var(--ink);
  transform: scaleX(0); transform-origin: 100% 50%;
  transition: transform 0.35s var(--ease);
}
.nav-links a:hover { color: var(--ink); }
.nav-links a:hover::after { transform: scaleX(1); transform-origin: 0 50%; }
.nav-cta { color: var(--ink) !important; display: inline-flex; align-items: center; gap: 8px; }
.nav-cta i {
  font-style: normal; font-family: var(--font-mono); font-size: 8px;
  letter-spacing: 0.1em; color: var(--bg);
  background: var(--ink); padding: 3px 7px;
}
.nav-version { font-size: 10px; letter-spacing: 0.2em; color: var(--faint); }
@media (max-width: 860px) { .nav-version { display: none; } }
@media (max-width: 640px) { .nav-links { display: none; } }

/* ---------- HERO ---------- */
.hero {
  position: relative; min-height: 100vh;
  display: flex; flex-direction: column; justify-content: center;
  padding: 140px clamp(20px, 6vw, 80px) 80px;
  overflow: hidden;
}
.hero-grid-bg {
  position: absolute; inset: 0; pointer-events: none;
  background:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 96px 96px;
  mask-image: radial-gradient(ellipse 80% 70% at 50% 40%, #000 20%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 40%, #000 20%, transparent 75%);
  opacity: 0.5;
}
.hero-inner { position: relative; z-index: 2; max-width: 900px; }
.eyebrow {
  font-size: 11px; letter-spacing: 0.34em; color: var(--muted);
  margin-bottom: 28px; display: flex; align-items: center; gap: 14px;
}
.eyebrow::before { content: ""; width: 42px; height: 1px; background: var(--line-strong); }
.hero-title {
  font-size: clamp(52px, 9.2vw, 128px);
  font-weight: 620;
  line-height: 0.98;
  letter-spacing: -0.015em;
  margin-bottom: 34px;
}
.hero-title .serif-italic { font-weight: 420; }
.hero-sub {
  font-size: clamp(15px, 1.5vw, 18px);
  color: var(--muted); max-width: 620px; margin-bottom: 44px;
}
.hero-cta { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 56px; }
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 15px 34px; text-decoration: none;
  font-size: 14px; letter-spacing: 0.1em; font-weight: 500;
  border: 1px solid var(--ink);
  transition: background 0.35s var(--ease), color 0.35s var(--ease), transform 0.35s var(--ease);
}
.btn-solid { background: var(--ink); color: var(--bg); }
.btn-solid:hover { background: transparent; color: var(--ink); transform: translateY(-2px); }
.btn-ghost { color: var(--ink); border-color: var(--line-strong); }
.btn-ghost:hover { border-color: var(--ink); transform: translateY(-2px); }
.hero-meta {
  display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
  font-size: 10px; letter-spacing: 0.26em; color: var(--faint);
}
.hero-meta i { font-style: normal; color: var(--line-strong); }
.hero-mark {
  position: absolute; right: clamp(-40px, 2vw, 90px); top: 50%;
  transform: translateY(-50%); z-index: 1;
  width: clamp(200px, 30vw, 420px); opacity: 0.9;
  animation: markFloat 7s ease-in-out infinite;
}
.hero-mark img { width: 100%; display: block; }
@keyframes markFloat {
  0%, 100% { translate: 0 0; }
  50% { translate: 0 -18px; }
}
@media (max-width: 900px) {
  .hero-mark { opacity: 0.16; right: -60px; top: 24%; transform: none; animation: none; }
}
.scroll-hint {
  position: absolute; bottom: 28px; left: 50%; transform: translateX(-50%);
  font-size: 10px; letter-spacing: 0.3em; color: var(--faint);
  animation: hintDrop 2.2s ease-in-out infinite;
}
@keyframes hintDrop { 0%, 100% { translate: 0 0; opacity: 0.6; } 50% { translate: 0 8px; opacity: 1; } }

/* ---------- 跑马灯 ---------- */
.marquee {
  border-top: 1px solid var(--line); border-bottom: 1px solid var(--line);
  padding: 20px 0; overflow: hidden; white-space: nowrap;
}
.marquee-track { display: inline-block; animation: marquee 30s linear infinite; }
.marquee-track span {
  font-family: var(--font-serif); font-style: italic;
  font-size: clamp(18px, 2.4vw, 28px); color: var(--faint);
}
@keyframes marquee { to { transform: translateX(-50%); } }

/* ---------- 通用 Section ---------- */
.section { padding: clamp(80px, 12vw, 160px) clamp(20px, 6vw, 80px); max-width: 1280px; margin: 0 auto; }
.section-label {
  font-size: 11px; letter-spacing: 0.3em; color: var(--faint);
  padding-bottom: 18px; border-bottom: 1px solid var(--line); margin-bottom: 56px;
}
.section-title {
  font-size: clamp(38px, 6vw, 76px);
  font-weight: 620; line-height: 1.04; letter-spacing: -0.01em;
  margin-bottom: clamp(48px, 7vw, 88px);
}
.section-title .serif-italic { font-weight: 420; }

/* ---------- 宣言区 ---------- */
.manifesto-quote { margin-bottom: clamp(56px, 8vw, 96px); }
.manifesto-quote p {
  font-family: var(--font-serif);
  font-size: clamp(28px, 4.4vw, 56px);
  font-weight: 420; line-height: 1.28; letter-spacing: 0.01em;
  max-width: 900px;
}
.manifesto-quote cite {
  display: block; font-style: normal; font-size: 10px;
  letter-spacing: 0.28em; color: var(--faint); margin-top: 28px;
}
.manifesto-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; background: var(--line); border: 1px solid var(--line); }
.manifesto-grid > div { background: var(--bg); padding: clamp(28px, 4vw, 52px); }
.manifesto-grid h3 {
  font-size: 13px; letter-spacing: 0.24em; font-weight: 600;
  margin-bottom: 18px; display: flex; align-items: center; gap: 12px;
}
.manifesto-grid h3::before { content: "—"; color: var(--faint); }
.manifesto-grid p { color: var(--muted); font-size: 15px; }
@media (max-width: 720px) { .manifesto-grid { grid-template-columns: 1fr; } }

/* ---------- 能力卡片 ---------- */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); }
.card {
  background: var(--bg); padding: clamp(26px, 3.4vw, 44px);
  position: relative; overflow: hidden;
  transition: background 0.45s var(--ease), color 0.45s var(--ease);
}
.card::before {
  content: ""; position: absolute; left: 0; top: 0;
  width: 100%; height: 2px; background: var(--ink);
  transform: scaleX(0); transform-origin: 0 50%;
  transition: transform 0.5s var(--ease);
}
.card:hover { background: var(--paper); color: var(--paper-ink); }
.card:hover::before { transform: scaleX(1); }
.card:hover p, .card:hover li { color: rgba(10, 10, 10, 0.66); }
.card:hover .card-index { color: rgba(10, 10, 10, 0.4); }
.card-index {
  font-size: 11px; letter-spacing: 0.2em; color: var(--faint);
  display: block; margin-bottom: 22px; transition: color 0.45s;
}
.card h3 { font-size: clamp(19px, 1.8vw, 23px); font-weight: 620; margin-bottom: 16px; line-height: 1.35; }
.card > p { color: var(--muted); font-size: 14px; margin-bottom: 18px; transition: color 0.45s; }
.card ul { list-style: none; }
.card li {
  color: var(--muted); font-size: 13px; padding: 10px 0 10px 20px;
  border-top: 1px solid var(--line); position: relative; transition: color 0.45s;
}
.card:hover li { border-top-color: var(--paper-line); }
.card li::before {
  content: ""; position: absolute; left: 0; top: 18px;
  width: 8px; height: 1px; background: currentColor;
}
@media (max-width: 1024px) { .cards { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) { .cards { grid-template-columns: 1fr; } }

/* ---------- 工作流 ---------- */
.steps { list-style: none; border-top: 1px solid var(--line); }
.step {
  display: grid; grid-template-columns: 130px 1fr 2fr; gap: clamp(16px, 3vw, 48px);
  align-items: baseline; padding: clamp(28px, 4vw, 48px) 0;
  border-bottom: 1px solid var(--line);
  transition: padding-left 0.45s var(--ease);
}
.step:hover { padding-left: 18px; }
.step-no { font-size: 11px; letter-spacing: 0.24em; color: var(--faint); }
.step h3 { font-size: clamp(22px, 2.6vw, 32px); font-weight: 620; }
.step p { color: var(--muted); font-size: 14.5px; }
@media (max-width: 720px) { .step { grid-template-columns: 1fr; gap: 10px; } }

/* ---------- 终端 ---------- */
.terminal {
  border: 1px solid var(--line-strong);
  background: #0e0e0e;
  box-shadow: 0 40px 90px rgba(0, 0, 0, 0.55);
}
.terminal-bar {
  display: flex; align-items: center; gap: 8px;
  padding: 13px 18px; border-bottom: 1px solid var(--line);
  background: #131312;
}
.tdot { width: 10px; height: 10px; border-radius: 50%; border: 1px solid var(--faint); }
.terminal-title { margin-left: auto; font-size: 10px; letter-spacing: 0.18em; color: var(--faint); }
.terminal-body {
  padding: clamp(22px, 3.6vw, 40px);
  font-size: clamp(12.5px, 1.35vw, 14.5px);
  line-height: 2.05; min-height: 340px;
  white-space: pre-wrap; word-break: break-all;
}
.tline { display: block; }
.t-prompt { color: var(--faint); }
.t-cmd { color: var(--ink); font-weight: 500; }
.t-out { color: var(--muted); }
.t-ok { color: var(--ink); }
.t-dim { color: var(--faint); }
.t-cursor {
  display: inline-block; width: 8px; height: 15px;
  background: var(--ink); vertical-align: -2px; margin-left: 2px;
  animation: blink 1s steps(1) infinite;
}
@keyframes blink { 50% { opacity: 0; } }
.terminal-note { margin-top: 22px; font-size: 11px; letter-spacing: 0.06em; color: var(--faint); }

/* ---------- 使用声明（反白） ---------- */
.notice { background: var(--paper); color: var(--paper-ink); max-width: none; }
.notice .section-label { color: rgba(10, 10, 10, 0.45); border-bottom-color: var(--paper-line); }
.notice .section-title .serif-italic { color: rgba(10, 10, 10, 0.72); }
.notice-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 1px; background: var(--paper-line); border: 1px solid var(--paper-line); }
.notice-item { background: var(--paper); padding: clamp(22px, 2.6vw, 34px); transition: background 0.4s, color 0.4s; }
.notice-item:hover { background: var(--paper-ink); color: var(--paper); }
.notice-item span { font-size: 10px; letter-spacing: 0.24em; opacity: 0.5; display: block; margin-bottom: 16px; }
.notice-item p { font-size: 13.5px; line-height: 1.85; }
.notice-item strong { font-weight: 700; }
@media (max-width: 1100px) { .notice-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .notice-grid { grid-template-columns: 1fr; } }

/* ---------- 页脚 ---------- */
.footer {
  padding: clamp(56px, 7vw, 88px) clamp(20px, 6vw, 80px);
  border-top: 1px solid var(--line);
  display: flex; align-items: center; justify-content: space-between; gap: 40px; flex-wrap: wrap;
}
.footer-brand { display: flex; align-items: center; gap: 18px; }
.footer-mark { width: 44px; height: 44px; }
.footer-word { font-weight: 700; letter-spacing: 0.14em; font-size: 17px; }
.footer-word em { display: block; font-style: normal; font-family: var(--font-mono); font-size: 8px; letter-spacing: 0.42em; color: var(--muted); margin-top: 2px; }
.footer-sub { font-size: 9px; letter-spacing: 0.22em; color: var(--faint); margin-top: 8px; }
.footer-note { font-size: 11px; color: var(--faint); max-width: 460px; letter-spacing: 0.04em; }

/* ---------- 进场动画 ---------- */
.reveal { opacity: 0; transform: translateY(30px); transition: opacity 0.9s var(--ease), transform 0.9s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .marquee-track, .hero-mark, .scroll-hint { animation: none; }
  html { scroll-behavior: auto; }
}