/* ============================================================
   obihuang.com ｜ Obi Huang 个人网站
   主题：锁定深色 ｜ 单一强调色 ｜ 圆角规则：按钮/胶囊全圆，卡片 16px
   ============================================================ */

:root {
  --bg: #151311;
  --bg-2: #1b1917;
  --panel: #201d1a;
  --panel-2: #262320;
  --line: rgba(255, 255, 255, 0.09);
  --line-strong: rgba(255, 255, 255, 0.16);
  --text: #f4f1ec;
  --muted: #b5b1a9;
  --faint: #8d897f;
  --accent: #ef6a3f;
  --accent-hover: #f87c52;
  --accent-soft: rgba(239, 106, 63, 0.14);
  --accent-line: rgba(239, 106, 63, 0.34);
  --ink-on-accent: #1a110b;
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC",
    sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", Menlo,
    Consolas, "Liberation Mono", monospace;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  color-scheme: dark;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

::selection { background: rgba(239, 106, 63, 0.35); color: #fff; }

a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
ul { list-style: none; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.skip-link {
  position: fixed;
  top: -48px;
  left: 16px;
  z-index: 100;
  padding: 0.5rem 1rem;
  background: var(--accent);
  color: var(--ink-on-accent);
  border-radius: 999px;
  font-size: 0.85rem;
  transition: top 0.2s var(--ease);
}
.skip-link:focus { top: 12px; }

/* ---------------- 按钮 ---------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  border-radius: 999px;
  font-weight: 600;
  white-space: nowrap;
  transition: transform 0.25s var(--ease), background 0.25s var(--ease),
    border-color 0.25s var(--ease), color 0.25s var(--ease);
}
.btn:active { transform: translateY(1px) scale(0.98); }

.btn-primary {
  background: var(--accent);
  color: var(--ink-on-accent);
}
.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

.btn-ghost {
  border: 1px solid var(--line-strong);
  color: var(--text);
}
.btn-ghost:hover {
  border-color: var(--accent-line);
  color: var(--accent);
  background: var(--accent-soft);
  transform: translateY(-1px);
}

.btn-lg { padding: 0.95rem 2rem; font-size: 1rem; }
.btn-nav { padding: 0.5rem 1.15rem; font-size: 0.88rem; }

/* ---------------- 导航 ---------------- */

.nav-sentinel { position: absolute; top: 0; height: 8px; width: 100%; }

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  height: 64px;
  transition: background 0.35s var(--ease), border-color 0.35s var(--ease);
  border-bottom: 1px solid transparent;
}
.nav.scrolled {
  background: rgba(21, 19, 17, 0.8);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-bottom-color: var(--line);
}

.nav-inner {
  max-width: 1200px;
  height: 100%;
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
  display: flex;
  align-items: center;
  gap: 2.5rem;
}

.brand {
  font-family: var(--mono);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}
.brand-tld { color: var(--faint); font-weight: 400; }

.nav-links {
  display: flex;
  gap: 1.9rem;
  margin-left: auto;
  font-size: 0.92rem;
  color: var(--muted);
}
.nav-links a {
  transition: color 0.2s var(--ease);
  padding: 0.25rem 0;
}
.nav-links a:hover { color: var(--text); }

/* ---------------- Hero ---------------- */

.hero {
  position: relative;
  min-height: 100dvh;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.hero-bg { position: absolute; inset: 0; pointer-events: none; }

.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-mask-image: radial-gradient(ellipse 90% 70% at 60% 40%, #000 30%, transparent 75%);
  mask-image: radial-gradient(ellipse 90% 70% at 60% 40%, #000 30%, transparent 75%);
}

.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(90px);
}
.hero-glow-a {
  width: 560px;
  height: 560px;
  right: -140px;
  top: -120px;
  background: radial-gradient(circle, rgba(239, 106, 63, 0.16), transparent 65%);
  animation: drift-a 16s ease-in-out infinite alternate;
}
.hero-glow-b {
  width: 460px;
  height: 460px;
  left: -160px;
  bottom: -140px;
  background: radial-gradient(circle, rgba(239, 106, 63, 0.09), transparent 65%);
  animation: drift-b 20s ease-in-out infinite alternate;
}
@keyframes drift-a {
  from { transform: translate(0, 0); }
  to { transform: translate(-60px, 50px); }
}
@keyframes drift-b {
  from { transform: translate(0, 0); }
  to { transform: translate(70px, -40px); }
}

.hero-ghost {
  position: absolute;
  right: -0.04em;
  bottom: -0.14em;
  font-family: var(--mono);
  font-weight: 700;
  font-size: clamp(8rem, 24vw, 19rem);
  line-height: 1;
  letter-spacing: -0.02em;
  color: transparent;
  -webkit-text-stroke: 1px rgba(255, 255, 255, 0.05);
  user-select: none;
}

.hero-inner {
  position: relative;
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  padding: 6.5rem clamp(1.25rem, 4vw, 2.5rem) 5rem;
}

.hero-eyebrow {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--muted);
  letter-spacing: 0.06em;
  margin-bottom: 1.6rem;
}
.hero-eyebrow::before {
  content: "";
  display: inline-block;
  width: 26px;
  height: 1px;
  background: var(--accent);
  vertical-align: middle;
  margin-right: 0.8rem;
}

.hero-title {
  font-size: clamp(2.55rem, 7.2vw, 4.7rem);
  font-weight: 800;
  line-height: 1.14;
  letter-spacing: 0.005em;
  max-width: 18em;
}
.hero-title em {
  font-style: normal;
  color: var(--accent);
}

.hero-sub {
  margin-top: 1.5rem;
  max-width: 40em;
  color: var(--muted);
  font-size: clamp(1rem, 1.6vw, 1.15rem);
}

.hero-cta {
  margin-top: 2.4rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
}

/* ---------------- 数据带 ---------------- */

.stats {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--bg-2);
}
.stats-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
  display: grid;
  grid-template-columns: repeat(4, 1fr);
}
.stat {
  padding: 2.4rem 1rem 2.4rem 0;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}
.stat + .stat { border-left: 1px solid var(--line); padding-left: 2rem; }
.stat-num {
  font-family: var(--mono);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  line-height: 1.1;
}
.stat-num i { font-style: normal; color: var(--accent); }
.stat-label { color: var(--muted); font-size: 0.9rem; }

/* ---------------- 通用区块 ---------------- */

section { scroll-margin-top: 76px; }

.section-head {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
  margin-bottom: 3.2rem;
}
.section-head h2 {
  font-size: clamp(1.85rem, 3.6vw, 2.6rem);
  font-weight: 800;
  line-height: 1.25;
}
.section-sub {
  margin-top: 0.8rem;
  color: var(--muted);
  max-width: 40em;
}

/* ---------------- 项目卡片 ---------------- */

.projects { padding: 7.5rem 0 6.5rem; }

.proj-grid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 1.3rem;
}

.span-3 { grid-column: span 3; }
.span-2 { grid-column: span 2; }

.proj-card {
  --pad-x: 2rem;
  --pad-top: 1.9rem;
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: var(--pad-top) var(--pad-x) 1.7rem;
  transition: transform 0.35s var(--ease), border-color 0.35s var(--ease),
    box-shadow 0.35s var(--ease);
}
.proj-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-line);
  box-shadow: 0 18px 44px rgba(0, 0, 0, 0.38);
}

/* 封面：贴齐卡片顶部，整图可点击 */
.card-cover {
  display: block;
  position: relative;
  margin: calc(-1 * var(--pad-top)) calc(-1 * var(--pad-x)) 1.5rem;
  border-radius: 15px 15px 0 0;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background: var(--bg-2);
}
.card-cover img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  transition: transform 0.5s var(--ease);
}
.card-cover:hover img,
.card-cover:focus-visible img { transform: scale(1.035); }
.cover-arrow {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 30px;
  height: 30px;
  padding: 7px;
  color: #fff;
  background: rgba(21, 19, 17, 0.6);
  -webkit-backdrop-filter: blur(4px);
  backdrop-filter: blur(4px);
  border-radius: 999px;
  opacity: 0;
  transform: translateY(-4px);
  transition: opacity 0.3s var(--ease), transform 0.3s var(--ease);
}
.card-cover:hover .cover-arrow,
.card-cover:focus-visible .cover-arrow {
  opacity: 1;
  transform: none;
}

/* 卡片底纹：与项目标识同一图案体系，右上角淡出 */
.proj-card::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  -webkit-mask-image: linear-gradient(205deg, #000, transparent 52%);
  mask-image: linear-gradient(205deg, #000, transparent 52%);
}
.card-lines::before {
  background: repeating-linear-gradient(
    45deg, rgba(239, 106, 63, 0.055) 0 1px, transparent 1px 12px);
}
.card-dots::before {
  background-image: radial-gradient(rgba(239, 106, 63, 0.08) 1px, transparent 1.4px);
  background-size: 14px 14px;
}
.card-cross::before {
  background:
    repeating-linear-gradient(45deg, rgba(239, 106, 63, 0.05) 0 1px, transparent 1px 13px),
    repeating-linear-gradient(-45deg, rgba(239, 106, 63, 0.05) 0 1px, transparent 1px 13px);
}
.card-waves::before {
  background: repeating-linear-gradient(
    0deg, rgba(239, 106, 63, 0.055) 0 1px, transparent 1px 12px);
}
.card-rings::before {
  background: repeating-radial-gradient(
    circle at 100% 0%, rgba(239, 106, 63, 0.07) 0 1px, transparent 1px 13px);
}

.card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.3rem;
  position: relative;
}

.card-name {
  font-size: 1.5rem;
  font-weight: 800;
  line-height: 1.2;
  position: relative;
}

.card-tag {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.55;
  margin-top: 0.35rem;
  position: relative;
}

.card-points {
  list-style: disc;
  padding-left: 1.15rem;
  margin-top: 1.1rem;
  position: relative;
}
.card-points li {
  color: var(--muted);
  font-size: 0.92rem;
  padding: 0.22rem 0;
}
.card-points li::marker { color: var(--accent); }

/* 产品 / 技术分区 */
.card-blocks {
  display: grid;
  gap: 1.15rem;
  margin-top: 1.15rem;
  position: relative;
}
.block-k {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--accent);
}
.block-k::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--line);
}
.card-block .card-points { margin-top: 0.5rem; }
.card-block .card-points li { font-size: 0.9rem; }

.card-foot {
  margin-top: auto;
  padding-top: 1.4rem;
  position: relative;
}
.card-foot .proj-meta { margin-top: 0; }

/* 项目标识：产品真实 logo（应用图标式满铺） */
.proj-mark {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  border: 1px solid var(--line);
  overflow: hidden;
  flex-shrink: 0;
  background: var(--bg-2);
}
.proj-mark img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* 状态胶囊 */
.chip {
  font-family: var(--mono);
  font-size: 0.74rem;
  color: var(--accent);
  border: 1px solid var(--accent-line);
  border-radius: 999px;
  padding: 0.28rem 0.75rem;
  white-space: nowrap;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.9rem;
}
.tags span {
  font-family: var(--mono);
  font-size: 0.74rem;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.22rem 0.7rem;
}

/* ---------------- 能力 ---------------- */

.caps {
  padding: 6.5rem 0;
  background: var(--bg-2);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.caps-grid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
  display: grid;
  grid-template-columns: 1fr 1.35fr;
  grid-template-areas:
    "prod feat"
    "arch feat";
  gap: 1.4rem;
}

.cap {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 2rem 2.1rem;
}
.cap-prod { grid-area: prod; }
.cap-arch { grid-area: arch; }
.cap-feature {
  grid-area: feat;
  background:
    linear-gradient(165deg, rgba(239, 106, 63, 0.16), rgba(239, 106, 63, 0.04) 45%, transparent 75%),
    var(--panel);
  border-color: var(--accent-line);
}

.cap h3 { font-size: 1.15rem; font-weight: 800; }
.cap-lead { color: var(--muted); margin: 0.35rem 0 1.1rem; }
.cap ul { list-style: disc; padding-left: 1.15rem; }
.cap li {
  color: var(--muted);
  font-size: 0.94rem;
  padding: 0.3rem 0;
}
.cap li::marker { color: var(--accent); }
.cap-certs {
  margin-top: 1.3rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  line-height: 1.8;
  color: var(--faint);
}
.cap-link {
  display: inline-block;
  margin-top: 1.4rem;
  font-family: var(--mono);
  font-size: 0.88rem;
  color: var(--accent);
  border-bottom: 1px solid var(--accent-line);
  padding-bottom: 2px;
  transition: border-color 0.25s var(--ease), color 0.25s var(--ease);
}
.cap-link:hover { color: var(--accent-hover); border-color: var(--accent-hover); }

/* ---------------- 方法 ---------------- */

.method { padding: 7rem 0; }

.method-grid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
}
.step { border-top: 2px solid var(--line-strong); padding-top: 1.3rem; }
.step h3 { font-size: 1.05rem; font-weight: 700; }
.step p { color: var(--muted); font-size: 0.9rem; margin-top: 0.5rem; }

/* ---------------- 经历 ---------------- */

.exp {
  padding: 6.5rem 0 7rem;
  background: var(--bg-2);
  border-top: 1px solid var(--line);
}

.bio {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
}
.bio p {
  max-width: 40em;
  color: var(--muted);
  font-size: clamp(1.02rem, 1.6vw, 1.15rem);
  line-height: 1.95;
}
.bio p + p { margin-top: 1.1rem; }

.bio .edu {
  margin-top: 2.2rem;
  color: var(--faint);
  font-size: 0.86rem;
  font-family: var(--mono);
}

/* ---------------- 联系 ---------------- */

.contact { padding: 8rem 0 0; overflow: hidden; }

.contact-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
}
.contact h2 {
  font-size: clamp(2.3rem, 5.6vw, 3.8rem);
  font-weight: 800;
  line-height: 1.18;
}
.contact h2 em {
  font-style: normal;
  color: var(--accent);
}
.contact p {
  color: var(--muted);
  margin-top: 1.1rem;
  max-width: 36em;
}
.contact-mail {
  display: inline-block;
  margin-top: 2.2rem;
  font-family: var(--mono);
  font-size: clamp(1.35rem, 3.4vw, 2.1rem);
  font-weight: 600;
  color: var(--accent);
  border-bottom: 1px solid var(--accent-line);
  padding-bottom: 4px;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease);
}
.contact-mail:hover {
  color: var(--accent-hover);
  border-color: var(--accent-hover);
}
.contact-meta {
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--faint);
  margin-top: 1.6rem;
}

.footer {
  margin-top: 6.5rem;
  border-top: 1px solid var(--line);
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  padding: 1.6rem clamp(1.25rem, 4vw, 2.5rem) 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--faint);
}
.foot-links { display: flex; gap: 1.4rem; }
.foot-links a { transition: color 0.2s var(--ease); }
.foot-links a:hover { color: var(--text); }

/* ---------------- 入场动画 ---------------- */

.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.75s var(--ease), transform 0.75s var(--ease);
}
.reveal.d1 { transition-delay: 0.08s; }
.reveal.d2 { transition-delay: 0.16s; }
.reveal.d3 { transition-delay: 0.24s; }
.reveal.d4 { transition-delay: 0.32s; }
.reveal.in {
  opacity: 1;
  transform: none;
}

/* ---------------- 响应式 ---------------- */

@media (max-width: 960px) {
  .caps-grid {
    grid-template-columns: 1fr;
    grid-template-areas: "prod" "arch" "feat";
  }
  .proj-grid { grid-template-columns: 1fr 1fr; }
  .proj-card { grid-column: auto; }
  .proj-card:last-child { grid-column: 1 / -1; }
  .method-grid {
    grid-template-columns: 1fr 1fr;
    gap: 1.8rem 2rem;
  }
}

@media (max-width: 720px) {
  .nav-links { display: none; }
  .nav-inner { justify-content: space-between; }

  .stats-inner { grid-template-columns: 1fr 1fr; }
  .stat { padding: 1.6rem 0.6rem 1.6rem 0; }
  .stat + .stat { padding-left: 1.2rem; }
  .stat:nth-child(3) { border-left: 0; padding-left: 0; }
  .stat:nth-child(n + 3) { border-top: 1px solid var(--line); }

  .projects { padding: 5.5rem 0 5rem; }
  .proj-grid { grid-template-columns: 1fr; gap: 1rem; }
  .proj-card:last-child { grid-column: auto; }
  .proj-card { --pad-x: 1.4rem; --pad-top: 1.5rem; padding: var(--pad-top) var(--pad-x) 1.6rem; }
  .card-name { font-size: 1.25rem; }

  .caps, .exp { padding: 5rem 0; }
  .method { padding: 5.5rem 0; }
  .cap { padding: 1.6rem 1.5rem; }

  .contact { padding-top: 6rem; }
  .footer { margin-top: 4.5rem; flex-direction: column; align-items: flex-start; }
}

/* ---------------- 降低动效 ---------------- */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hero-glow-a, .hero-glow-b { animation: none; }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .btn,
  .proj-card,
  .nav { transition: none; }
}