/* ============================================================
   Celebrate Rock — Computer Systems Design
   Jiujiang Helei Network Technology Co., Ltd.
   ============================================================ */

/* --- Custom Properties ----------------------------------- */
:root {
  /* Palette */
  --color-bg:        #0a0b0f;
  --color-bg-alt:    #111318;
  --color-bg-card:   #16181f;
  --color-bg-raised: #1c1e26;
  --color-border:    #262832;
  --color-border-light: #2e303b;

  --color-text:      #e4e5ea;
  --color-text-mid:  #9a9cb0;
  --color-text-dim:  #5e6075;

  --color-accent:    #00d4aa;
  --color-accent-2:  #6c5ce7;
  --color-accent-3:  #ff6b35;
  --color-accent-glow: #00ffc8;

  --color-surface-1: #14161d;
  --color-surface-2: #191b24;

  /* Typography */
  --font-sans:  Inter, system-ui, -apple-system, sans-serif;
  --font-mono:  JetBrains Mono, SF Mono, Fira Code, monospace;

  /* Spacing */
  --space-xs:  0.25rem;
  --space-sm:  0.5rem;
  --space-md:  1rem;
  --space-lg:  1.5rem;
  --space-xl:  2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Layout */
  --max-width: 1200px;
  --header-h:  72px;

  /* Radii */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* Transitions */
  --ease-out:  cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --duration-fast: 150ms;
  --duration-base: 300ms;
  --duration-slow: 500ms;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-h);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  overflow-x: hidden;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
button { cursor: pointer; font: inherit; color: inherit; border: none; background: none; }
input, textarea { font: inherit; color: inherit; }

::selection {
  background: var(--color-accent);
  color: var(--color-bg);
}

/* --- Grid Overlay ---------------------------------------- */
.grid-overlay {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background-image:
    linear-gradient(to right, var(--color-border) 1px, transparent 1px),
    linear-gradient(to bottom, var(--color-border) 1px, transparent 1px);
  background-size: 80px 80px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, black 20%, transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, black 20%, transparent 70%);
}

/* --- Container ------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

/* --- Header ---------------------------------------------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-h);
  background: var(--color-bg);
  border-bottom: 1px solid transparent;
  transition: border-color var(--duration-base) var(--ease-out),
              background var(--duration-base) var(--ease-out);
}

.site-header.scrolled {
  border-bottom-color: var(--color-border);
  background: hsl(228, 20%, 6%);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
  z-index: 101;
}

.logo-icon {
  color: var(--color-accent);
  font-size: 1.35rem;
  filter: drop-shadow(0 0 8px hsl(166, 100%, 35%));
  transition: transform var(--duration-base) var(--ease-out);
}

.logo:hover .logo-icon {
  transform: rotate(45deg);
}

.logo-accent {
  color: var(--color-accent);
}

/* Nav */
.main-nav ul {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.main-nav a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-mid);
  transition: color var(--duration-fast) var(--ease-out);
  position: relative;
}

.main-nav a:hover,
.main-nav a.active {
  color: var(--color-text);
}

.main-nav a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--duration-base) var(--ease-out);
}

.main-nav a:hover::after,
.main-nav a.active::after {
  width: 100%;
}

.nav-divider {
  width: 1px;
  height: 18px;
  background: var(--color-border);
  margin: 0 var(--space-xs);
}

/* Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  z-index: 101;
  padding: var(--space-sm);
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--duration-base) var(--ease-out),
              opacity var(--duration-base) var(--ease-out);
}

.menu-toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* --- Hero ------------------------------------------------ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: calc(var(--header-h) + var(--space-4xl)) 0 var(--space-4xl);
  overflow: hidden;
}

.hero .container {
  position: relative;
  z-index: 1;
}

/* Hero Particles */
.hero-particles {
  position: absolute;
  inset: 0;
  overflow: hidden;
}

.particle {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  opacity: 0.15;
  animation: float 20s ease-in-out infinite;
}

.p1 { width: 400px; height: 400px; background: var(--color-accent-2); top: -100px; right: -100px; }
.p2 { width: 300px; height: 300px; background: var(--color-accent); top: 40%; left: -80px; animation-delay: -5s; }
.p3 { width: 250px; height: 250px; background: var(--color-accent-3); bottom: -60px; right: 30%; animation-delay: -10s; }
.p4 { width: 200px; height: 200px; background: var(--color-accent); top: 20%; right: 10%; animation-delay: -15s; }
.p5 { width: 350px; height: 350px; background: var(--color-accent-2); bottom: -120px; left: 20%; animation-delay: -7s; }

@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  25% { transform: translate(30px, -30px) scale(1.05); }
  50% { transform: translate(-20px, -50px) scale(0.95); }
  75% { transform: translate(10px, 20px) scale(1.02); }
}

/* Hero Badge */
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-xs) var(--space-md);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 100px;
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: var(--color-text-mid);
  margin-bottom: var(--space-xl);
}

.badge-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 6px var(--color-accent);
}

/* Hero Title */
.hero-title {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 900;
  line-height: 1.08;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-lg);
}

.hero-highlight {
  background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-2) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--color-text-mid);
  max-width: 620px;
  line-height: 1.7;
  margin-bottom: var(--space-xl);
}

.hero-actions {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
  margin-bottom: var(--space-3xl);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.8rem 1.6rem;
  font-size: 0.925rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: transform var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out),
              background var(--duration-fast) var(--ease-out),
              border-color var(--duration-fast) var(--ease-out);
}

.btn:active { transform: scale(0.97); }

.btn-primary {
  background: var(--color-accent);
  color: var(--color-bg);
  border: 2px solid var(--color-accent);
}

.btn-primary:hover {
  box-shadow: 0 0 30px hsl(166, 100%, 25%);
}

.btn-outline {
  border: 2px solid var(--color-border-light);
  color: var(--color-text);
}

.btn-outline:hover {
  border-color: var(--color-text-mid);
}

.btn-full { width: 100%; justify-content: center; }

/* Hero Metrics */
.hero-metrics {
  display: flex;
  gap: var(--space-2xl);
  flex-wrap: wrap;
}

.metric {
  display: flex;
  flex-direction: column;
}

.metric-value {
  font-size: 2rem;
  font-weight: 800;
  font-family: var(--font-mono);
  color: var(--color-accent);
  letter-spacing: -0.02em;
}

.metric-label {
  font-size: 0.85rem;
  color: var(--color-text-dim);
}

/* --- Sections -------------------------------------------- */
.section {
  padding: var(--space-4xl) 0;
  position: relative;
  z-index: 1;
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto var(--space-3xl);
}

.section-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-accent);
  margin-bottom: var(--space-md);
  font-family: var(--font-mono);
}

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-md);
  line-height: 1.2;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--color-text-mid);
  line-height: 1.7;
}

/* --- About Cards ----------------------------------------- */
.about-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
}

.about-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: border-color var(--duration-base) var(--ease-out),
              transform var(--duration-base) var(--ease-out);
}

.about-card:hover {
  border-color: var(--color-border-light);
  transform: translateY(-4px);
}

.about-card-icon {
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg-raised);
  border-radius: var(--radius-md);
  color: var(--color-accent);
  margin-bottom: var(--space-lg);
}

.about-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.about-card p {
  font-size: 0.875rem;
  color: var(--color-text-mid);
  line-height: 1.65;
}

/* --- Services List --------------------------------------- */
.services-list {
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--color-border);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.service-item {
  display: grid;
  grid-template-columns: 80px 1fr 200px;
  gap: var(--space-lg);
  align-items: center;
  padding: var(--space-xl);
  background: var(--color-bg-card);
  transition: background var(--duration-fast) var(--ease-out);
}

.service-item:hover {
  background: var(--color-bg-raised);
}

.service-number {
  font-family: var(--font-mono);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--color-accent);
  opacity: 0.7;
}

.service-content h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: var(--space-xs);
}

.service-content p {
  font-size: 0.875rem;
  color: var(--color-text-mid);
  line-height: 1.6;
}

.service-tags {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
  justify-content: flex-end;
}

.service-tags li {
  font-size: 0.75rem;
  font-weight: 500;
  font-family: var(--font-mono);
  padding: 0.25rem 0.65rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 100px;
  color: var(--color-text-mid);
}

/* --- Contact --------------------------------------------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: var(--space-3xl);
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

.contact-block h3 {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-dim);
  margin-bottom: var(--space-xs);
}

.contact-block p,
.contact-block a {
  font-size: 1rem;
  color: var(--color-text);
  line-height: 1.7;
}

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

/* Form */
.contact-form {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.form-group label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-dim);
}

.form-group input,
.form-group textarea {
  padding: 0.7rem 0.9rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 0.925rem;
  transition: border-color var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px hsl(166, 100%, 20%);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--color-text-dim);
}

.form-feedback {
  font-size: 0.85rem;
  min-height: 1.2em;
}

.form-feedback.success { color: var(--color-accent); }
.form-feedback.error { color: var(--color-accent-3); }

/* --- Legal Pages ----------------------------------------- */
.legal-hero {
  padding: calc(var(--header-h) + var(--space-3xl)) 0 var(--space-2xl);
  text-align: center;
  position: relative;
  z-index: 1;
}

.legal-hero .hero-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
}

.legal-hero .hero-subtitle {
  font-size: 0.95rem;
  color: var(--color-text-dim);
}

.legal-content {
  padding-top: 0;
}

.prose {
  max-width: 780px;
  margin: 0 auto;
}

.prose h2 {
  font-size: 1.35rem;
  font-weight: 700;
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
  color: var(--color-text);
}

.prose h2:first-child {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}

.prose p {
  color: var(--color-text-mid);
  line-height: 1.8;
  margin-bottom: var(--space-md);
}

.prose a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

/* --- Footer ---------------------------------------------- */
.site-footer {
  position: relative;
  z-index: 1;
  border-top: 1px solid var(--color-border);
  padding: var(--space-3xl) 0 var(--space-xl);
  background: var(--color-bg-alt);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

.footer-brand p {
  color: var(--color-text-dim);
  font-size: 0.85rem;
  margin-top: var(--space-sm);
}

.footer-nav h4,
.footer-contact h4 {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-dim);
  margin-bottom: var(--space-md);
}

.footer-nav ul,
.footer-contact ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.footer-nav a,
.footer-contact a {
  font-size: 0.9rem;
  color: var(--color-text-mid);
  transition: color var(--duration-fast) var(--ease-out);
}

.footer-nav a:hover,
.footer-contact a:hover {
  color: var(--color-accent);
}

.footer-bottom {
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
}

.footer-bottom p {
  font-size: 0.8rem;
  color: var(--color-text-dim);
}

/* --- Responsive ------------------------------------------ */
@media (max-width: 1024px) {
  .about-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .service-item {
    grid-template-columns: 60px 1fr 160px;
    gap: var(--space-md);
    padding: var(--space-lg);
  }

  .contact-grid {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }

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

@media (max-width: 768px) {
  :root {
    --header-h: 64px;
  }

  .container {
    padding: 0 var(--space-lg);
  }

  .menu-toggle {
    display: flex;
  }

  .main-nav {
    position: fixed;
    inset: 0;
    background: var(--color-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--duration-base) var(--ease-out);
  }

  .main-nav.open {
    opacity: 1;
    pointer-events: auto;
  }

  .main-nav ul {
    flex-direction: column;
    gap: var(--space-xl);
    text-align: center;
  }

  .main-nav a {
    font-size: 1.2rem;
  }

  .nav-divider {
    width: 40px;
    height: 1px;
    margin: var(--space-sm) 0;
  }

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

  .service-item {
    grid-template-columns: 1fr;
    gap: var(--space-sm);
  }

  .service-tags {
    justify-content: flex-start;
  }

  .hero-metrics {
    gap: var(--space-xl);
  }

  .metric-value {
    font-size: 1.5rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }
}

@media (max-width: 480px) {
  .hero-actions {
    flex-direction: column;
  }

  .btn {
    justify-content: center;
  }
}