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

:root {
  --color-bg: #0a0a0a;
  --color-surface: #141414;
  --color-border: #222;
  --color-text: #e5e5e5;
  --color-text-muted: #888;
  --color-accent: #ff3c00;
  --color-accent-glow: rgba(255, 60, 0, 0.15);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Consolas", monospace;
  --max-width: 1100px;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-text);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--color-accent);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ========== Navigation ========== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.nav__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav__logo {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--color-accent);
}

.nav__logo:hover {
  color: var(--color-accent);
}

.nav__links {
  list-style: none;
  display: flex;
  gap: 32px;
}

.nav__links a {
  font-size: 0.875rem;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
}

.nav__links a:hover {
  color: var(--color-text);
}

.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav__toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  transition: 0.2s;
}

/* ========== Hero ========== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px 80px;
  background:
    radial-gradient(ellipse at 50% 0%, var(--color-accent-glow) 0%, transparent 60%),
    var(--color-bg);
}

.hero__title {
  font-size: clamp(3rem, 10vw, 7rem);
  font-weight: 800;
  letter-spacing: 0.2em;
  line-height: 1.1;
  color: #fff;
}

.hero__subtitle {
  margin-top: 12px;
  font-size: 1rem;
  letter-spacing: 0.3em;
  color: var(--color-text-muted);
  text-transform: uppercase;
}

.hero__divider {
  width: 48px;
  height: 2px;
  background: var(--color-accent);
  margin: 32px auto;
}

.hero__tagline {
  font-size: 1.125rem;
  color: var(--color-text);
  margin-bottom: 48px;
}

/* Countdown */
.countdown {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-bottom: 32px;
}

.countdown__item {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 72px;
}

.countdown__number {
  font-size: 2.5rem;
  font-weight: 700;
  font-family: var(--font-mono);
  color: #fff;
  line-height: 1.2;
}

.countdown__label {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  letter-spacing: 0.1em;
  margin-top: 4px;
}

.hero__date {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  letter-spacing: 0.15em;
}

/* ========== Sections ========== */
.section {
  padding: 100px 0;
}

.section__title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 16px;
  letter-spacing: 0.05em;
}

.section__desc {
  text-align: center;
  color: var(--color-text-muted);
  margin-bottom: 56px;
  font-size: 1rem;
}

/* ========== About ========== */
.about {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.about__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
  margin-top: 48px;
}

.about__text p {
  margin-bottom: 16px;
  color: var(--color-text-muted);
  font-size: 1rem;
  line-height: 1.9;
}

.about__text strong {
  color: var(--color-text);
}

.about__stats {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.stat {
  display: flex;
  align-items: baseline;
  gap: 16px;
}

.stat__number {
  font-size: 3rem;
  font-weight: 800;
  color: var(--color-accent);
  font-family: var(--font-mono);
  line-height: 1;
}

.stat__label {
  font-size: 1rem;
  color: var(--color-text-muted);
}

/* ========== Event ========== */
.event__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.event__card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 40px 28px;
  transition: border-color 0.3s, transform 0.3s;
}

.event__card:hover {
  border-color: var(--color-accent);
  transform: translateY(-4px);
}

.event__icon {
  font-size: 1.5rem;
  color: var(--color-accent);
  margin-bottom: 20px;
}

.event__card h3 {
  font-size: 1.125rem;
  margin-bottom: 12px;
  font-weight: 600;
}

.event__card p {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.8;
}

/* ========== Join / QR ========== */
.join {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.join__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 16px;
}

.join__card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 32px 24px;
  text-align: center;
  transition: border-color 0.3s, transform 0.3s;
}

.join__card:hover {
  border-color: var(--color-accent);
  transform: translateY(-4px);
}

.join__card--primary {
  border-color: var(--color-accent);
  box-shadow: 0 0 32px var(--color-accent-glow);
}

.join__qr {
  width: 200px;
  height: 200px;
  margin: 0 auto 20px;
  background: #fff;
  padding: 12px;
  border-radius: 6px;
}

.join__qr img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: contain;
  image-rendering: pixelated;
}

.join__card h3 {
  font-size: 1.125rem;
  margin-bottom: 8px;
  font-weight: 600;
}

.join__card p {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

@media (max-width: 768px) {
  .join__grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  .join__qr {
    width: 180px;
    height: 180px;
  }
}

/* ========== Footer ========== */
.footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 64px 0 32px;
}

.footer__inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer__brand h2 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--color-accent);
  margin-bottom: 8px;
}

.footer__brand p {
  color: var(--color-text-muted);
  font-size: 0.875rem;
}

.footer__company {
  margin-top: 12px;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.footer__contact h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.footer__contact p {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.footer__email {
  color: var(--color-accent);
  font-family: var(--font-mono);
  margin-top: 8px;
}

.footer__bottom {
  border-top: 1px solid var(--color-border);
  padding-top: 24px;
  text-align: center;
}

.footer__bottom p {
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.footer__bottom a {
  color: var(--color-text-muted);
}

.footer__bottom a:hover {
  color: var(--color-accent);
}

/* ========== Mobile ========== */
@media (max-width: 768px) {
  .nav__links {
    display: none;
  }

  .nav__toggle {
    display: flex;
  }

  /* Mobile menu open state */
  .nav.open .nav__links {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: rgba(10, 10, 10, 0.95);
    backdrop-filter: blur(12px);
    padding: 24px;
    gap: 20px;
    border-bottom: 1px solid var(--color-border);
  }

  .hero__title {
    letter-spacing: 0.1em;
  }

  .countdown {
    gap: 12px;
  }

  .countdown__number {
    font-size: 1.75rem;
  }

  .countdown__item {
    min-width: 56px;
  }

  .about__grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .about__stats {
    flex-direction: row;
    justify-content: space-between;
  }

  .stat {
    flex-direction: column;
    align-items: center;
    gap: 4px;
    text-align: center;
  }

  .stat__number {
    font-size: 2rem;
  }

  .event__grid {
    grid-template-columns: 1fr;
  }

  .footer__inner {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}