/* ============================================================
   Design System — inspired by Xnors Studio
   Paper / Ink / Signal
   ============================================================ */

/* ===== Reset ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* ===== Design Tokens ===== */
:root {
  --c-paper: #F6F6F1;
  --c-paper-2: #EDEDE6;
  --c-ink: #14140F;
  --c-ink-2: #6A6A5E;
  --c-ink-3: #9C9C8E;
  --c-line: #D8D8CC;
  --c-signal: #FF3D00;

  --font-display: "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-body: "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "Space Mono", "SFMono-Regular", Consolas, monospace;

  --font-size-kicker: 12px;
  --font-size-caption: 13px;
  --font-size-base: 16px;
  --font-size-lg: 18px;
  --font-size-h3: 20px;
  --font-size-h2: clamp(26px, 3.4vw, 38px);
  --font-size-h1: clamp(40px, 7vw, 78px);

  --weight-regular: 400;
  --weight-medium: 500;
  --weight-bold: 700;
  --weight-black: 900;

  --line-height-body: 1.7;
  --line-height-heading: 1.15;

  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-5: 48px;
  --space-6: 64px;
  --space-7: 96px;
  --space-8: 128px;

  --max-width: 1180px;
  --padding-mobile: 16px;
  --padding-tablet: 32px;
  --padding-desktop: 56px;

  --line-fine: 1px;
  --line-medium: 2px;
  --line-thick: 3px;

  --ease: cubic-bezier(.22, 1, .36, 1);
  --t-fast: .18s ease;
  --t-base: .26s ease;
  --t-slow: .45s var(--ease);

  color-scheme: light;
}

/* ===== Dark Mode ===== */
:root[data-theme="dark"] {
  --c-paper: #14140F;
  --c-paper-2: #1C1C16;
  --c-ink: #EDEDE6;
  --c-ink-2: #9C9C8E;
  --c-ink-3: #6A6A5E;
  --c-line: #2A2A22;
  --c-signal: #FF6B3D;

  color-scheme: dark;
}

/* ===== Base ===== */
html {
  scroll-padding-top: 84px; /* 与 JS 里的 -84 偏移对齐:原生锚点跳转也停在导航栏下方 */
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  font-weight: var(--weight-regular);
  line-height: var(--line-height-body);
  color: var(--c-ink);
  background: var(--c-paper);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--c-ink);
  text-decoration: none;
  transition: color var(--t-fast);
}

img {
  max-width: 100%;
  display: block;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--padding-mobile);
}

@media (min-width: 600px) {
  .container {
    padding: 0 var(--padding-tablet);
  }
}

@media (min-width: 960px) {
  .container {
    padding: 0 var(--padding-desktop);
  }
}

/* ===== Focus ===== */
:focus-visible {
  outline: 2px solid var(--c-signal);
  outline-offset: 2px;
  border-radius: 2px;
}

/* ===== Navbar ===== */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 100;
  background: transparent;
  backdrop-filter: none;
  transition: background var(--t-base), border-color var(--t-base), transform var(--t-base);
  border-bottom: var(--line-fine) solid transparent;
}

.navbar.scrolled {
  background: var(--c-paper);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom-color: var(--c-line);
}

.navbar.hidden {
  transform: translateY(-100%);
}

.nav-inner {
  display: flex;
  align-items: center;
  height: 64px;
  gap: var(--space-4);
}

/* Logo */
.nav-logo {
  flex-shrink: 0;
  color: var(--c-ink);
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: var(--weight-bold);
  line-height: 1;
  letter-spacing: .05em;
}

.logo-mark {
  display: inline-flex;
  align-items: center;
  gap: 1px;
}

.logo-img {
  display: block;
  width: 28px;
  height: 28px;
  border-radius: 6px;
  margin-left: 2px;
}

/* Nav links */
.nav-links {
  display: flex;
  gap: var(--space-3);
  margin-left: auto;
}

.nav-link {
  font-family: var(--font-mono);
  font-size: var(--font-size-kicker);
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--c-ink-2);
  font-weight: var(--weight-bold);
  transition: color var(--t-fast);
  position: relative;
  padding: 4px 0;
}

.nav-link:hover {
  color: var(--c-ink);
}

.nav-link.active {
  color: var(--c-ink);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--c-signal);
}

/* Nav actions */
.nav-actions {
  display: flex;
  gap: 6px;
  margin-left: var(--space-2);
}

.theme-toggle,
.lang-toggle {
  background: none;
  border: var(--line-fine) solid var(--c-line);
  border-radius: 4px;
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: var(--weight-bold);
  letter-spacing: .05em;
  color: var(--c-ink-2);
  cursor: pointer;
  transition: color var(--t-fast), border-color var(--t-fast), background var(--t-fast);
  line-height: 1.4;
}

.theme-toggle:hover,
.lang-toggle:hover {
  color: var(--c-ink);
  border-color: var(--c-ink-2);
  background: var(--c-paper-2);
}

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
  width: 32px;
  height: 32px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  margin-left: auto;
  z-index: 101;
}

.hamburger-line {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--c-ink);
  transition: transform var(--t-base), opacity var(--t-fast);
  border-radius: 1px;
}

.hamburger.open .hamburger-line:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.hamburger.open .hamburger-line:nth-child(2) {
  opacity: 0;
}

.hamburger.open .hamburger-line:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* ===== Hero ===== */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 80px 0 40px;
  position: relative;
  overflow: hidden;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
  align-items: center;
  width: 100%;
}

.hero-main {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-2);
}

.avatar {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--c-line);
  margin-bottom: var(--space-1);
  user-select: none;
}

.hero-kicker {
  font-family: var(--font-mono);
  font-size: var(--font-size-kicker);
  letter-spacing: .3em;
  color: var(--c-ink-2);
  text-transform: uppercase;
}

.hero-heading {
  font-family: var(--font-display);
  font-size: var(--font-size-h1);
  font-weight: var(--weight-black);
  line-height: var(--line-height-heading);
  color: var(--c-ink);
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-family: var(--font-body);
  font-size: var(--font-size-lg);
  color: var(--c-ink-2);
  font-weight: var(--weight-regular);
  max-width: 480px;
  margin-top: var(--space-1);
}

.hero-subtitle .hl {
  color: var(--c-signal);
  font-weight: var(--weight-medium);
}

.hero-links {
  display: flex;
  gap: var(--space-3);
  margin-top: var(--space-3);
}

.hero-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--c-ink-2);
  transition: color var(--t-fast);
  padding: 4px 0;
}

.hero-link:hover {
  color: var(--c-ink);
}

/* Terminal signature */
.hero-signature {
  display: flex;
  justify-content: center;
  align-items: center;
}

.terminal {
  font-family: var(--font-mono);
  font-size: 15px;
  line-height: 1.8;
  color: var(--c-ink-2);
  background: var(--c-paper-2);
  border: var(--line-fine) solid var(--c-line);
  border-radius: 8px;
  padding: var(--space-3) var(--space-4);
  min-width: 240px;
}

.terminal .prompt {
  color: var(--c-signal);
  font-weight: var(--weight-bold);
}

.terminal .cmd {
  color: var(--c-ink);
}

.terminal .output {
  color: var(--c-ink-3);
  padding-left: calc(1em + 8px);
}

.blink {
  animation: blink 1s step-end infinite;
}

@keyframes blink {
  50% { opacity: 0; }
}

/* Scroll hint */
.scroll-hint {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  color: var(--c-ink-3);
  opacity: 0.5;
  animation: bounce 2.5s infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(6px); }
}

/* ===== Sections ===== */
.section {
  padding: var(--space-7) 0;
}

.section:last-of-type {
  padding-bottom: var(--space-8);
}

.section-kicker {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--font-size-kicker);
  letter-spacing: .3em;
  color: var(--c-ink-2);
  text-transform: uppercase;
  margin-bottom: var(--space-1);
}

.section-title {
  font-family: var(--font-display);
  font-size: var(--font-size-h2);
  font-weight: var(--weight-black);
  line-height: var(--line-height-heading);
  color: var(--c-ink);
  margin-bottom: var(--space-3);
}

.section-body {
  color: var(--c-ink-2);
  max-width: 640px;
  line-height: var(--line-height-body);
  font-size: var(--font-size-base);
}

/* ===== Project Cards ===== */
.project-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
}

.project-card {
  border: var(--line-fine) solid var(--c-line);
  border-radius: 8px;
  padding: var(--space-4);
  transition: border-color var(--t-base), box-shadow var(--t-base);
  background: var(--c-paper);
}

.project-card:hover {
  border-color: var(--c-ink-2);
  box-shadow: 0 2px 16px rgba(0,0,0,0.04);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: var(--space-2);
}

.project-tags span {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .05em;
  color: var(--c-ink-3);
  border: var(--line-fine) solid var(--c-line);
  padding: 2px 10px;
  border-radius: 999px;
  transition: color var(--t-base), border-color var(--t-base);
}

.project-card:hover .project-tags span {
  border-color: var(--c-ink-3);
}

.project-tag-idx {
  color: var(--c-signal) !important;
  border: var(--line-fine) solid var(--c-signal) !important;
  font-weight: var(--weight-bold);
}

.project-title {
  font-family: var(--font-display);
  font-size: var(--font-size-h3);
  font-weight: var(--weight-bold);
  color: var(--c-ink);
  margin-bottom: var(--space-1);
  transition: color var(--t-base);
}

.project-card:hover .project-title {
  color: var(--c-signal);
}

.project-desc {
  font-size: var(--font-size-caption);
  color: var(--c-ink-2);
  line-height: var(--line-height-body);
  margin-bottom: var(--space-2);
}

.project-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: var(--weight-bold);
  color: var(--c-ink-2);
  letter-spacing: .05em;
  transition: color var(--t-fast);
}

.project-link:hover {
  color: var(--c-signal);
}

/* ===== Contact ===== */
.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-2);
}

.contact-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--c-ink-2);
  border: var(--line-fine) solid var(--c-line);
  border-radius: 6px;
  padding: 8px 16px;
  transition: color var(--t-fast), border-color var(--t-fast), background var(--t-fast);
}

.contact-link:hover {
  color: var(--c-ink);
  border-color: var(--c-ink-2);
  background: var(--c-paper-2);
}

.contact-email-display {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: var(--space-3);
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--c-ink-2);
  letter-spacing: .02em;
  transition: color var(--t-fast);
}

.contact-email-display:hover {
  color: var(--c-ink);
}

/* ===== Footer ===== */
.site-footer {
  border-top: var(--line-fine) solid var(--c-line);
  padding: var(--space-5) 0 var(--space-4);
}

.footer-links {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-1);
  margin-bottom: var(--space-4);
}

.footer-links-title {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: var(--weight-bold);
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--c-ink-3);
  margin-bottom: 2px;
}

.footer-link {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--c-ink-2);
  transition: color var(--t-fast);
}

.footer-link:hover {
  color: var(--c-signal);
}

.footer-copy {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--c-ink-3);
  letter-spacing: .05em;
}

/* ===== Back to Top ===== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  left: 32px;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: var(--line-fine) solid var(--c-line);
  border-radius: 8px;
  background: var(--c-paper);
  color: var(--c-ink-2);
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--t-base), border-color var(--t-base), color var(--t-base), background var(--t-base);
}

.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
}

.back-to-top:hover {
  border-color: var(--c-ink-2);
  color: var(--c-ink);
  background: var(--c-paper-2);
}

@media (max-width: 768px) {
  .back-to-top {
    bottom: 20px;
    left: 20px;
    width: 40px;
    height: 40px;
  }
}

/* ===== Copy Toast ===== */
.copy-toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translateX(-50%);
  background: var(--c-ink);
  color: var(--c-paper);
  font-family: var(--font-mono);
  font-size: 12px;
  padding: 6px 16px;
  border-radius: 999px;
  z-index: 200;
  animation: toast-in var(--t-base);
  white-space: nowrap;
}

@keyframes toast-in {
  from { opacity: 0; transform: translateX(-50%) translateY(8px); }
  to   { opacity: 1; transform: translateX(-50%) translateY(0); }
}

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  html {
    scroll-behavior: auto; /* 尊重系统减动设置 */
  }
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .hero-inner {
    grid-template-columns: 1fr;
    gap: var(--space-4);
    text-align: center;
  }

  .hero-main {
    align-items: center;
  }

  .hero-subtitle {
    max-width: 100%;
  }

  .hero-links {
    justify-content: center;
  }

  .hero-signature {
    display: none;
  }

  .nav-links {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: 240px;
    flex-direction: column;
    gap: 0;
    padding: 80px var(--space-4) var(--space-4);
    background: var(--c-paper);
    border-left: var(--line-fine) solid var(--c-line);
    transform: translateX(100%);
    transition: transform var(--t-base);
    margin-left: 0;
  }

  .nav-links .nav-actions {
    display: flex;
    flex-direction: row;
    gap: var(--space-2);
    margin-left: 0;
    padding-top: var(--space-3);
    border-top: var(--line-fine) solid var(--c-line);
  }

  .nav-links .nav-actions .theme-toggle,
  .nav-links .nav-actions .lang-toggle {
    flex: 1;
    padding: 10px 8px;
  }

  .nav-links.open {
    transform: translateX(0);
  }

  .nav-link {
    padding: 12px 0;
    font-size: 14px;
    border-bottom: var(--line-fine) solid var(--c-line);
  }

  .nav-actions {
    display: none;
  }

  .hamburger {
    display: flex;
  }

  .section-kicker {
    text-align: center;
    display: block;
  }

  .section-title {
    text-align: center;
  }

  .section-body {
    text-align: center;
    max-width: 100%;
  }

  .contact-links {
    justify-content: center;
  }

  .contact-email-display {
    text-align: center;
  }
}

@media (min-width: 600px) {
  .project-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 960px) {
  .project-grid {
    grid-template-columns: 1fr 1fr 1fr;
  }
}