/* ============================================================
   优可得 youkede — 个人主页
   黑 × 白 × 朱砂：一个关于「科技平权」的页面
   ============================================================ */

:root {
  --ink: #050505;          /* 纯黑底 */
  --ink-soft: #0e0e0e;
  --paper: #f2f2f2;        /* 素白 */
  --paper-dim: rgba(242, 242, 242, 0.62);
  --paper-faint: rgba(242, 242, 242, 0.34);
  --cinnabar: #d84b35;     /* 朱砂 */
  --ash: #9a9a9a;          /* 素灰 */
  --serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --mono: "SF Mono", "Menlo", "Courier New", monospace;
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--ink);
  color: var(--paper);
  font-family: var(--serif);
  line-height: 1.9;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

::selection { background: var(--cinnabar); color: var(--paper); }

/* ---------- 颗粒与光 ---------- */

.grain {
  position: fixed;
  inset: -50%;
  width: 200%;
  height: 200%;
  pointer-events: none;
  z-index: 60;
  opacity: 0.05;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='300' height='300' filter='url(%23n)'/%3E%3C/svg%3E");
  animation: grain-shift 1.2s steps(4) infinite;
}

@keyframes grain-shift {
  0%   { transform: translate(0, 0); }
  25%  { transform: translate(-2%, 1%); }
  50%  { transform: translate(1%, -2%); }
  75%  { transform: translate(-1%, -1%); }
  100% { transform: translate(0, 0); }
}

#light {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

/* ---------- 页头 ---------- */

.site-head {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 50;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.6rem clamp(1.5rem, 5vw, 4rem);
  mix-blend-mode: difference;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--paper);
  text-decoration: none;
  font-size: 1.05rem;
  letter-spacing: 0.35em;
}

.brand-mark {
  width: 0.7em;
  height: 0.7em;
  border-radius: 50%;
  background: var(--cinnabar);
  box-shadow: 0 0 12px rgba(216, 75, 53, 0.8);
}

.site-nav { display: flex; gap: 2.2rem; }

.site-nav a {
  color: var(--paper-dim);
  text-decoration: none;
  font-size: 0.9rem;
  letter-spacing: 0.3em;
  transition: color 0.4s;
  position: relative;
}

.site-nav a::after {
  content: "";
  position: absolute;
  left: 0; bottom: -0.35em;
  width: 100%;
  height: 1px;
  background: var(--cinnabar);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.5s var(--ease-out);
}

.site-nav a:hover { color: var(--paper); }
.site-nav a:hover::after { transform: scaleX(1); transform-origin: left; }

/* ---------- 首屏 ---------- */

.hero {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 0 1.5rem;
}

.hero-kicker {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.6em;
  color: var(--ash);
  margin-bottom: 2.5rem;
}

.hero-title {
  font-size: clamp(3rem, 11vw, 8.5rem);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: 0.08em;
}

.hero-title .char {
  display: inline-block;
  opacity: 0;
  transform: translateY(0.35em) rotate(2deg);
  filter: blur(8px);
  animation: char-in 1.2s var(--ease-out) forwards;
}

.hero-title .char:nth-child(1) { animation-delay: 0.15s; }
.hero-title .char:nth-child(2) { animation-delay: 0.32s; }
.hero-title .char:nth-child(3) { animation-delay: 0.49s; }
.hero-title .char:nth-child(4) { animation-delay: 0.66s; color: var(--cinnabar); }

@keyframes char-in {
  to { opacity: 1; transform: none; filter: blur(0); }
}

.hero-sub {
  margin-top: 2.2rem;
  font-size: clamp(1rem, 2.4vw, 1.35rem);
  letter-spacing: 0.28em;
  color: var(--paper-dim);
}

.hero-side {
  position: absolute;
  right: clamp(1rem, 4vw, 3rem);
  top: 50%;
  transform: translateY(-50%);
  writing-mode: vertical-rl;
  letter-spacing: 0.55em;
  font-size: 0.85rem;
  color: var(--paper-faint);
}

.hero-scroll {
  position: absolute;
  bottom: 2.4rem;
  left: 50%;
  transform: translateX(-50%);
  width: 1px;
  height: 4.5rem;
  background: var(--paper-faint);
  overflow: hidden;
}

.hero-scroll span {
  position: absolute;
  left: 0; top: -40%;
  width: 100%;
  height: 40%;
  background: var(--cinnabar);
  animation: scroll-hint 2s ease-in-out infinite;
}

@keyframes scroll-hint {
  0%   { top: -40%; }
  60%, 100% { top: 110%; }
}

/* ---------- 流动横幅 ---------- */

.marquee {
  position: relative;
  z-index: 1;
  border-top: 1px solid rgba(242, 242, 242, 0.12);
  border-bottom: 1px solid rgba(242, 242, 242, 0.12);
  padding: 1.1rem 0;
  overflow: hidden;
  white-space: nowrap;
}

.marquee-track {
  display: inline-flex;
  animation: marquee 30s linear infinite;
}

.marquee-track span {
  font-family: var(--mono);
  font-size: 0.8rem;
  letter-spacing: 0.45em;
  color: var(--paper-faint);
}

@keyframes marquee {
  to { transform: translateX(-50%); }
}

/* ---------- 章节通用 ---------- */

section { position: relative; z-index: 1; }

.section-title {
  display: flex;
  align-items: baseline;
  gap: 1.2rem;
  font-size: clamp(1.8rem, 4.5vw, 2.8rem);
  font-weight: 700;
  letter-spacing: 0.2em;
  padding: 0 clamp(1.5rem, 6vw, 6rem);
  margin-bottom: clamp(3rem, 7vw, 5rem);
}

.section-title em {
  font-style: normal;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.4em;
  color: var(--ash);
}

.section-no {
  font-size: 0.85rem;
  color: var(--cinnabar);
  letter-spacing: 0.3em;
  border: 1px solid rgba(216, 75, 53, 0.5);
  padding: 0.2em 0.55em;
  transform: translateY(-0.4em);
}

/* ---------- 观点 ---------- */

.views { padding: clamp(6rem, 14vw, 11rem) 0; }

.view-list {
  list-style: none;
  max-width: 72rem;
  margin: 0 auto;
  padding: 0 clamp(1.5rem, 6vw, 6rem);
}

.view-item {
  display: flex;
  align-items: baseline;
  gap: clamp(1.2rem, 3.5vw, 3rem);
  padding: clamp(1.6rem, 3.5vw, 2.6rem) 0;
  border-bottom: 1px solid rgba(242, 242, 242, 0.12);
  transition: padding-left 0.6s var(--ease-out);
}

.view-item:first-child { border-top: 1px solid rgba(242, 242, 242, 0.12); }

.view-item:hover { padding-left: 1.2rem; }

.view-no {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--cinnabar);
  flex-shrink: 0;
}

.view-item p {
  font-size: clamp(1.35rem, 3.4vw, 2.3rem);
  font-weight: 600;
  letter-spacing: 0.06em;
  line-height: 1.6;
  transition: color 0.5s;
}

.view-item:hover p { color: var(--ash); }

/* ---------- 手记 ---------- */

.notes {
  padding: clamp(6rem, 14vw, 11rem) 0;
  background: var(--ink-soft);
}

.note-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: rgba(242, 242, 242, 0.1);
  border-top: 1px solid rgba(242, 242, 242, 0.1);
  border-bottom: 1px solid rgba(242, 242, 242, 0.1);
  margin: 0 clamp(1.5rem, 6vw, 6rem);
}

.note {
  background: var(--ink-soft);
  padding: clamp(2.2rem, 4vw, 3.2rem);
  transition: background 0.6s;
}

.note:hover { background: #161616; }

.note h3 {
  font-size: 1.3rem;
  letter-spacing: 0.4em;
  color: var(--cinnabar);
  margin-bottom: 1.4rem;
}

.note h3::after {
  content: "";
  display: block;
  width: 2rem;
  height: 1px;
  background: var(--ash);
  margin-top: 0.9rem;
  opacity: 0.6;
}

.note p {
  color: var(--paper-dim);
  font-size: 0.98rem;
  letter-spacing: 0.05em;
}

/* ---------- 关于 ---------- */

.about { padding: clamp(6rem, 14vw, 11rem) 0 clamp(5rem, 10vw, 8rem); }

.about-body {
  max-width: 44rem;
  margin: 0 auto;
  padding: 0 clamp(1.5rem, 6vw, 6rem);
}

.about-lead {
  font-size: clamp(1.4rem, 3.2vw, 2rem);
  line-height: 2;
  letter-spacing: 0.08em;
  margin-bottom: 2.5rem;
}

.about-lead strong {
  color: var(--cinnabar);
  font-weight: 700;
}

.about-body > p:not(.about-lead) {
  color: var(--paper-dim);
  letter-spacing: 0.06em;
  margin-bottom: 1.6rem;
}

/* ---------- 页脚 ---------- */

.site-foot {
  position: relative;
  z-index: 1;
  border-top: 1px solid rgba(242, 242, 242, 0.12);
  padding: 3.5rem 1.5rem 3rem;
  text-align: center;
}

.foot-brand {
  font-size: 1.15rem;
  letter-spacing: 0.5em;
  margin-bottom: 1.2rem;
}

.foot-brand span {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--ash);
  letter-spacing: 0.4em;
}

.foot-note {
  font-size: 0.8rem;
  color: var(--paper-faint);
  letter-spacing: 0.12em;
  margin-bottom: 0.9rem;
}

.foot-beian a {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--paper-faint);
  text-decoration: none;
  letter-spacing: 0.08em;
  transition: color 0.4s;
}

.foot-beian a:hover { color: var(--paper); }

/* ---------- 入场动效 ---------- */

.reveal {
  opacity: 0;
  transform: translateY(2.2rem);
  transition: opacity 1s var(--ease-out), transform 1s var(--ease-out);
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

/* ---------- 响应式 ---------- */

@media (max-width: 640px) {
  .site-nav { gap: 1.3rem; }
  .site-nav a { font-size: 0.8rem; letter-spacing: 0.2em; }
  .hero-side { display: none; }
  .view-item { flex-direction: column; gap: 0.5rem; }
  .view-item:hover { padding-left: 0; }
  .note-grid { grid-template-columns: 1fr; }
}

/* ---------- 减少动态 ---------- */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .grain, .marquee-track, .hero-scroll span { animation: none; }
  .hero-title .char { animation: none; opacity: 1; transform: none; filter: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
}