/* ── Design Tokens ── */
:root {
  --bg:        #0d1117;
  --bg-2:      #161b22;
  --accent:    #38f9d7;
  --text:      #e6edf3;
  --text-2:    #8b949e;
  --border:    #21262d;

  --font-en: 'Geist', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-cn: 'PingFang SC', 'Hiragino Sans GB', -apple-system, sans-serif;

  --r: 8px;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-en);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

/* ── Hero ── */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 64px 24px;
  /* subtle dot grid */
  background-image: radial-gradient(circle, #21262d 1px, transparent 1px);
  background-size: 32px 32px;
  /* dark vignette over the grid */
  background-color: var(--bg);
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, transparent 40%, var(--bg) 80%);
  pointer-events: none;
}

.hero-inner {
  position: relative;
  text-align: center;
  max-width: 640px;
}

.label {
  display: inline-block;
  font-size: 13px;
  font-weight: 400;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 24px;
}

.hero h1 {
  font-family: var(--font-en);
  font-size: clamp(48px, 10vw, 80px);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--text);
  margin-bottom: 16px;
}

.tagline {
  font-family: var(--font-cn);
  font-size: clamp(16px, 2.5vw, 20px);
  color: var(--text-2);
  margin-bottom: 32px;
}

.accent-line {
  width: 48px;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
  margin: 0 auto;
}

.scroll-hint {
  position: absolute;
  bottom: 32px;
  font-size: 20px;
  color: var(--text-2);
  animation: bob 2s ease-in-out infinite;
  transition: color 0.2s;
}
.scroll-hint:hover { color: var(--accent); }

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

/* ── Sections ── */
.section { padding: 96px 24px; }

.section--contact {
  border-top: 1px solid var(--border);
}

.container {
  max-width: 900px;
  margin: 0 auto;
}

.section-title {
  font-family: var(--font-en);
  font-size: 32px;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 48px;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -8px;
  width: 100%;
  height: 2px;
  background: var(--accent);
  border-radius: 1px;
}

/* ── Project Grid ── */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}

.card {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--r);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  transition: border-color 0.2s, transform 0.2s;
}
.card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
}

.card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.card-title {
  font-family: var(--font-cn);
  font-size: 20px;
  font-weight: 600;
  color: var(--text);
}

.card-link {
  flex-shrink: 0;
  color: var(--text-2);
  transition: color 0.2s;
  padding: 4px;
  display: none; /* 项目未开放时隐藏，开放后改为 flex */
}
.card-link:hover { color: var(--accent); }

.card-desc {
  font-family: var(--font-cn);
  font-size: 14px;
  color: var(--text-2);
  line-height: 1.7;
  flex: 1;
}

.mini-program-button {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  color: var(--text-2);
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--r);
  padding: 8px 16px;
  font-family: var(--font-cn);
  font-size: 14px;
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s, background-color 0.2s;
}

.mini-program-button:hover,
.mini-program-button:focus-visible {
  color: var(--text);
  background: rgba(56, 249, 215, 0.08);
  border-color: var(--accent);
  outline: none;
}

.mini-program-button__action {
  color: var(--accent);
  font-weight: 500;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  font-size: 12px;
  font-weight: 500;
  color: var(--accent);
  background: rgba(56, 249, 215, 0.08);
  border: 1px solid rgba(56, 249, 215, 0.2);
  border-radius: 4px;
  padding: 2px 10px;
  letter-spacing: 0.02em;
}

/* ── Contact ── */
.contact-inner {
  text-align: center;
}

.contact-desc {
  font-family: var(--font-cn);
  font-size: 18px;
  color: var(--text-2);
  margin-bottom: 32px;
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-bottom: 64px;
}

.social-link-wrap {
  position: relative;
}

.social-link {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  font-weight: 500;
  font-family: inherit;
  color: var(--text-2);
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--r);
  padding: 10px 20px;
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s;
}
.social-link:hover {
  color: var(--accent);
  border-color: var(--accent);
}

.qr-tooltip {
  position: absolute;
  bottom: calc(100% + 12px);
  left: 50%;
  transform: translateX(-50%) translateY(6px);
  background: #fff;
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s;
  /* arrow */
  filter: drop-shadow(0 4px 16px rgba(0,0,0,0.4));
}
.qr-tooltip::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 8px solid transparent;
  border-top-color: #fff;
}

.social-link-wrap:hover .qr-tooltip {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.qr-tooltip img {
  display: block;
  width: 180px;
  height: 180px;
  object-fit: contain;
}

.qr-label {
  font-family: var(--font-cn);
  font-size: 13px;
  color: #666;
}

/* ── Mini Program Dialog ── */
.qr-dialog {
  width: min(calc(100% - 32px), 384px);
  color: var(--text);
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px;
  margin: auto;
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.48);
}

.qr-dialog::backdrop {
  background: rgba(13, 17, 23, 0.8);
  backdrop-filter: blur(8px);
}

.qr-dialog__close {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  color: var(--text-2);
  background: transparent;
  border: 0;
  border-radius: var(--r);
  font-size: 24px;
  line-height: 1;
  cursor: pointer;
}

.qr-dialog__close:hover,
.qr-dialog__close:focus-visible {
  color: var(--accent);
  outline: 1px solid var(--accent);
}

.qr-dialog__content {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.qr-dialog__eyebrow {
  margin-bottom: 8px;
  color: var(--accent);
  font-family: var(--font-cn);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.qr-dialog__title {
  margin-bottom: 24px;
  font-family: var(--font-cn);
  font-size: 24px;
  font-weight: 600;
}

.qr-dialog__image {
  display: block;
  width: min(100%, 248px);
  height: auto;
  border-radius: var(--r);
}

.qr-dialog__hint {
  margin-top: 16px;
  color: var(--text-2);
  font-family: var(--font-cn);
  font-size: 14px;
}

.copyright {
  font-size: 13px;
  color: var(--border);
  letter-spacing: 0.04em;
}


/* ── Scroll Animations ── */
.animate-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.animate-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* stagger cards */
.card:nth-child(2) { transition-delay: 0.1s; }

/* ── Toast ── */
.toast {
  position: fixed;
  top: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(-12px);
  background: var(--bg-2);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: var(--font-cn);
  font-size: 14px;
  padding: 10px 24px;
  border-radius: var(--r);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s, transform 0.25s;
  z-index: 999;
}
.toast--show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}


/* ── Mobile ── */
@media (max-width: 480px) {
  .section { padding: 64px 16px; }
  .grid { grid-template-columns: 1fr; }
  .social-links { flex-direction: column; align-items: center; }
  .qr-dialog { padding: 24px; }
}