/* ABOUTME: 闫宝龙抖音推广网站主样式 - 极简黑白风格 */
/* Reset and base styles */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --black: #000000;
  --white: #FFFFFF;
  --gray-900: #1A1A1A;
  --gray-800: #222222;
  --gray-700: #333333;
  --gray-500: #666666;
  --gray-400: #888888;
  --gray-300: #999999;
  --gray-200: #CCCCCC;
  --gray-100: #E5E5E5;
  --gray-50: #F5F5F5;
  --radius: 2px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font-cn: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

body {
  background: var(--white);
  color: var(--gray-700);
  font-family: var(--font-cn);
  font-weight: 400;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

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

ul, ol {
  list-style: none;
}

/* ===== Navigation ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  transition: all var(--transition);
  background: transparent;
}

.nav.scrolled {
  background: rgba(0, 0, 0, 0.95);
  backdrop-filter: blur(10px);
  box-shadow: 0 1px 0 var(--gray-900);
}

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: padding var(--transition);
}

.nav.scrolled .nav-inner {
  padding: 12px 40px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0;
  color: var(--white);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
  white-space: nowrap;
}

.nav-logo .name {
  font-size: 1.375rem;
  position: relative;
}

.nav-logo .reg {
  font-size: 0.55rem;
  position: relative;
  top: -0.7em;
  margin-left: 1px;
  font-weight: 400;
}

.nav-logo .divider {
  display: inline-block;
  width: 1px;
  height: 18px;
  background: rgba(255,255,255,0.5);
  margin: 0 12px;
  vertical-align: middle;
}

.nav-logo .sub {
  font-size: 0.875rem;
  font-weight: 400;
  color: rgba(255,255,255,0.7);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-menu a {
  color: rgba(255, 255, 255, 0.75);
  font-size: 0.875rem;
  font-weight: 400;
  position: relative;
  padding: 4px 0;
  transition: color var(--transition);
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--white);
  transition: width var(--transition);
}

.nav-menu a:hover {
  color: var(--white);
}

.nav-menu a:hover::after {
  width: 100%;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  background: none;
  border: none;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--white);
  transition: all var(--transition);
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(4px, 5px);
}

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

.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(4px, -5px);
}

/* ===== Hero Banner ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--black);
  overflow: hidden;
}

.hero-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0.15;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 0 20px;
  max-width: 800px;
}

.hero-tag {
  display: inline-block;
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.5);
  border: 1px solid rgba(255,255,255,0.2);
  padding: 6px 20px;
  margin-bottom: 40px;
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.8s 0.3s forwards;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 24px;
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.8s 0.5s forwards;
}

.hero h1 .highlight {
  position: relative;
  display: inline-block;
}

.hero h1 .highlight::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--white);
  opacity: 0.3;
}

.hero-desc {
  font-size: 1.125rem;
  color: rgba(255,255,255,0.6);
  line-height: 1.8;
  margin-bottom: 48px;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.8s 0.7s forwards;
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 40px;
  border: 1px solid var(--white);
  color: var(--white);
  font-size: 0.875rem;
  letter-spacing: 0.1em;
  transition: all var(--transition);
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.8s 0.9s forwards;
}

.hero-cta:hover {
  background: var(--white);
  color: var(--black);
}

.hero-cta svg {
  width: 16px;
  height: 16px;
  transition: transform var(--transition);
}

.hero-cta:hover svg {
  transform: translateX(4px);
}

.hero-scroll {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  color: rgba(255,255,255,0.3);
  font-size: 0.75rem;
  letter-spacing: 0.15em;
  writing-mode: vertical-rl;
  animation: scrollHint 2s infinite;
}

@keyframes fadeInUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scrollHint {
  0%, 100% { opacity: 0.3; transform: translateX(-50%) translateY(0); }
  50% { opacity: 0.6; transform: translateX(-50%) translateY(8px); }
}

/* ===== Common Section ===== */
.section {
  padding: 100px 40px;
  max-width: 1200px;
  margin: 0 auto;
}

.section-dark {
  background: var(--gray-900);
  max-width: none;
  padding-left: 40px;
  padding-right: 40px;
}

.section-dark .section {
  padding-left: 0;
  padding-right: 0;
}

.section-header {
  margin-bottom: 60px;
}

.section-label {
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--gray-400);
  margin-bottom: 16px;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--black);
  letter-spacing: -0.02em;
  line-height: 1.3;
}

.section-dark .section-title {
  color: var(--white);
}

.section-dark .section-label {
  color: var(--gray-400);
}

.section-line {
  width: 40px;
  height: 1px;
  background: var(--gray-300);
  margin-top: 20px;
}

.section-dark .section-line {
  background: rgba(255,255,255,0.2);
}

/* ===== Services ===== */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--gray-100);
}

.service-card {
  background: var(--white);
  padding: 40px 32px;
  transition: all var(--transition);
  cursor: default;
}

.service-card:hover {
  background: var(--gray-50);
  transform: translateY(-2px);
}

.service-icon {
  width: 40px;
  height: 40px;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.service-icon svg {
  width: 28px;
  height: 28px;
  stroke: var(--black);
  stroke-width: 1.5;
  fill: none;
}

.service-card h3 {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--black);
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}

.service-card p {
  font-size: 0.875rem;
  color: var(--gray-500);
  line-height: 1.8;
}

/* ===== Why Choose ===== */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: rgba(255,255,255,0.08);
}

.advantage-card {
  padding: 48px 40px;
  background: var(--gray-900);
  transition: all var(--transition);
}

.advantage-card:hover {
  background: var(--gray-800);
}

.advantage-num {
  font-size: 3rem;
  font-weight: 200;
  color: rgba(255,255,255,0.15);
  line-height: 1;
  margin-bottom: 20px;
}

.advantage-card h3 {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 12px;
}

.advantage-card p {
  font-size: 0.875rem;
  color: var(--gray-400);
  line-height: 1.8;
}

/* ===== Process ===== */
.process-steps {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0;
  position: relative;
}

.process-step {
  text-align: center;
  padding: 40px 20px;
  position: relative;
}

.process-step::after {
  content: '';
  position: absolute;
  top: 56px;
  right: -1px;
  width: calc(100% - 56px);
  height: 1px;
  background: var(--gray-200);
  z-index: 0;
}

.process-step:last-child::after {
  display: none;
}

.process-num {
  width: 56px;
  height: 56px;
  border: 1px solid var(--gray-200);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: 700;
  color: var(--gray-500);
  margin: 0 auto 20px;
  position: relative;
  z-index: 1;
  background: var(--white);
  transition: all var(--transition);
}

.process-step:hover .process-num {
  border-color: var(--black);
  color: var(--black);
}

.process-step h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--black);
  margin-bottom: 8px;
}

.process-step p {
  font-size: 0.8125rem;
  color: var(--gray-500);
  line-height: 1.7;
}

/* ===== Stats ===== */
.stats-bar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--gray-200);
}

.stat-item {
  padding: 48px 32px;
  text-align: center;
  background: var(--white);
}

.stat-num {
  font-size: 2.75rem;
  font-weight: 700;
  color: var(--black);
  letter-spacing: -0.03em;
  line-height: 1;
  margin-bottom: 8px;
}

.stat-num .unit {
  font-size: 1.25rem;
  font-weight: 400;
  margin-left: 2px;
}

.stat-label {
  font-size: 0.8125rem;
  color: var(--gray-400);
  letter-spacing: 0.05em;
}

/* ===== FAQ ===== */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--gray-100);
}

.faq-item:first-child {
  border-top: 1px solid var(--gray-100);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 24px 0;
  background: none;
  border: none;
  cursor: pointer;
  font-family: var(--font-cn);
  font-size: 1rem;
  font-weight: 600;
  color: var(--black);
  text-align: left;
  transition: color var(--transition);
  line-height: 1.6;
}

.faq-question:hover {
  color: var(--gray-500);
}

.faq-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  margin-left: 20px;
  position: relative;
  transition: transform var(--transition);
}

.faq-icon::before,
.faq-icon::after {
  content: '';
  position: absolute;
  background: var(--black);
  transition: all var(--transition);
}

.faq-icon::before {
  width: 14px;
  height: 1px;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.faq-icon::after {
  width: 1px;
  height: 14px;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.faq-item.active .faq-icon::after {
  transform: translate(-50%, -50%) rotate(90deg);
  opacity: 0;
}

.faq-item.active .faq-question {
  color: var(--gray-500);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), padding 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.faq-answer-inner {
  padding-bottom: 24px;
  font-size: 0.9375rem;
  color: var(--gray-500);
  line-height: 1.9;
}

.faq-item.active .faq-answer {
  max-height: 300px;
}

/* ===== About ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: start;
}

.about-image {
  position: relative;
  width: 100%;
  aspect-ratio: 3/4;
  overflow: hidden;
  background: var(--gray-100);
}

.about-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.about-image:hover img {
  transform: scale(1.03);
}

.about-image::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--black);
}

.about-content h3 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--black);
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.about-role {
  font-size: 0.875rem;
  color: var(--gray-400);
  margin-bottom: 28px;
  letter-spacing: 0.05em;
}

.about-text {
  font-size: 0.9375rem;
  color: var(--gray-500);
  line-height: 2;
  margin-bottom: 24px;
}

.about-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 32px;
}

.about-tag {
  padding: 6px 16px;
  border: 1px solid var(--gray-200);
  font-size: 0.75rem;
  color: var(--gray-500);
  letter-spacing: 0.05em;
  transition: all var(--transition);
}

.about-tag:hover {
  border-color: var(--black);
  color: var(--black);
}

/* ===== Contact ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: start;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.contact-icon {
  width: 40px;
  height: 40px;
  border: 1px solid var(--gray-200);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.contact-icon svg {
  width: 18px;
  height: 18px;
  stroke: var(--black);
  stroke-width: 1.5;
  fill: none;
}

.contact-label {
  font-size: 0.75rem;
  color: var(--gray-400);
  letter-spacing: 0.1em;
  margin-bottom: 4px;
}

.contact-value {
  font-size: 1rem;
  font-weight: 600;
  color: var(--black);
}

.contact-value a {
  transition: color var(--transition);
}

.contact-value a:hover {
  color: var(--gray-500);
}

.contact-qr {
  text-align: center;
}

.contact-qr img {
  width: 180px;
  height: 180px;
  margin-bottom: 12px;
  border: 1px solid var(--gray-200);
}

.contact-qr p {
  font-size: 0.8125rem;
  color: var(--gray-400);
}

/* ===== Footer ===== */
.footer {
  background: var(--black);
  padding: 60px 40px 0;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
}

.footer-links-title {
  font-size: 0.75rem;
  color: rgba(255,255,255,0.4);
  letter-spacing: 0.15em;
  margin-bottom: 20px;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 12px 24px;
  margin-bottom: 40px;
}

.footer-links a {
  font-size: 0.8125rem;
  color: rgba(255,255,255,0.5);
  transition: color var(--transition);
  white-space: nowrap;
}

.footer-links a:hover {
  color: var(--white);
}

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 24px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-copyright {
  font-size: 0.75rem;
  color: rgba(255,255,255,0.3);
  line-height: 1.8;
}

.footer-copyright a {
  color: rgba(255,255,255,0.4);
  transition: color var(--transition);
}

.footer-copyright a:hover {
  color: rgba(255,255,255,0.7);
}

.footer-icp {
  font-size: 0.75rem;
}

.footer-icp a {
  color: rgba(255,255,255,0.3);
  transition: color var(--transition);
}

.footer-icp a:hover {
  color: rgba(255,255,255,0.5);
}

/* ===== Mobile Menu ===== */
.nav-mobile {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
  background: rgba(0,0,0,0.95);
  z-index: 999;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 28px;
}

.nav-mobile.open {
  display: flex;
}

.nav-mobile a {
  color: rgba(255,255,255,0.7);
  font-size: 1.25rem;
  font-weight: 400;
  transition: color var(--transition);
}

.nav-mobile a:hover {
  color: var(--white);
}

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

  .process-steps {
    grid-template-columns: repeat(3, 1fr);
  }

  .process-step:nth-child(3)::after {
    display: none;
  }

  .stats-bar {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-links {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-inner {
    padding: 16px 20px;
  }

  .hero h1 {
    font-size: 2.25rem;
  }

  .hero-desc {
    font-size: 1rem;
  }

  .section {
    padding: 64px 20px;
  }

  .section-title {
    font-size: 1.75rem;
  }

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

  .service-card {
    padding: 28px 20px;
  }

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

  .advantage-card {
    padding: 32px 20px;
  }

  .process-steps {
    grid-template-columns: repeat(2, 1fr);
    gap: 0;
  }

  .process-step::after {
    display: none;
  }

  .stats-bar {
    grid-template-columns: 1fr 1fr;
  }

  .stat-item {
    padding: 32px 20px;
  }

  .stat-num {
    font-size: 2rem;
  }

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

  .about-image {
    max-width: 320px;
  }

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

  .footer-links {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }

  .footer {
    padding: 40px 20px 0;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.75rem;
  }

  .nav-logo .name {
    font-size: 1.125rem;
  }

  .nav-logo .sub {
    font-size: 0.75rem;
  }

  .process-steps {
    grid-template-columns: 1fr;
  }

  .stats-bar {
    grid-template-columns: 1fr;
  }

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

/* ===== Utility ===== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}