/* 视频处理工具 - 官方静态站点 */
:root {
  --blue-900: #0c3d7a;
  --blue-800: #0f4c9a;
  --blue-700: #1565c0;
  --blue-600: #1e6fd9;
  --blue-500: #2563eb;
  --blue-400: #3b82f6;
  --blue-100: #dbeafe;
  --blue-50: #eff6ff;
  --white: #ffffff;
  --gray-900: #0f172a;
  --gray-700: #334155;
  --gray-500: #64748b;
  --gray-200: #e2e8f0;
  --gray-100: #f1f5f9;
  --shadow-sm: 0 1px 3px rgba(15, 76, 154, 0.08);
  --shadow-md: 0 8px 24px rgba(15, 76, 154, 0.12);
  --shadow-lg: 0 20px 48px rgba(15, 76, 154, 0.16);
  --radius: 12px;
  --radius-lg: 20px;
  --max-width: 1120px;
  --header-h: 64px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--gray-900);
  background: var(--white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--blue-600);
  text-decoration: none;
}

a:hover {
  color: var(--blue-800);
}

.container {
  width: min(100% - 32px, var(--max-width));
  margin-inline: auto;
}

/* Header */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--gray-200);
  z-index: 100;
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--gray-900);
}

.logo-icon {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--blue-500), var(--blue-700));
  display: grid;
  place-items: center;
  color: var(--white);
  font-size: 18px;
  box-shadow: var(--shadow-sm);
}

.nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav a {
  color: var(--gray-700);
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav a:hover {
  color: var(--blue-600);
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border: 1px solid var(--gray-200);
  border-radius: 8px;
  background: var(--white);
  cursor: pointer;
  padding: 0;
}

.nav-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 4px auto;
  background: var(--gray-700);
  border-radius: 1px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--blue-500), var(--blue-700));
  color: var(--white);
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35);
}

.btn-primary:hover {
  color: var(--white);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.45);
}

.btn-outline {
  background: var(--white);
  color: var(--blue-600);
  border: 1.5px solid var(--blue-200, var(--blue-100));
}

.btn-outline:hover {
  background: var(--blue-50);
  color: var(--blue-700);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.875rem;
}

/* Hero */
.hero {
  padding: calc(var(--header-h) + 64px) 0 80px;
  background:
    radial-gradient(ellipse 80% 60% at 50% -10%, rgba(37, 99, 235, 0.14), transparent),
    linear-gradient(180deg, var(--blue-50) 0%, var(--white) 70%);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: var(--white);
  border: 1px solid var(--blue-100);
  border-radius: 999px;
  font-size: 0.85rem;
  color: var(--blue-700);
  margin-bottom: 20px;
  box-shadow: var(--shadow-sm);
}

.hero-badge .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #22c55e;
}

.hero h1 {
  font-size: clamp(2rem, 4.5vw, 3rem);
  line-height: 1.15;
  margin: 0 0 20px;
  letter-spacing: -0.02em;
}

.hero h1 em {
  font-style: normal;
  color: var(--blue-600);
}

.hero-desc {
  font-size: 1.1rem;
  color: var(--gray-500);
  margin: 0 0 32px;
  max-width: 540px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 28px;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  font-size: 0.875rem;
  color: var(--gray-500);
}

.hero-meta strong {
  color: var(--gray-900);
}

.hero-visual {
  position: relative;
}

.app-preview {
  background: var(--white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--gray-200);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.app-preview-bar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 12px 16px;
  background: var(--gray-100);
  border-bottom: 1px solid var(--gray-200);
}

.app-preview-bar span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--gray-200);
}

.app-preview-bar span:nth-child(1) { background: #fca5a5; }
.app-preview-bar span:nth-child(2) { background: #fcd34d; }
.app-preview-bar span:nth-child(3) { background: #86efac; }

.app-preview-body {
  padding: 24px;
  background: linear-gradient(160deg, var(--blue-50), var(--white));
}

.preview-flow {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.preview-step {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 16px;
  background: var(--white);
  border-radius: var(--radius);
  border: 1px solid var(--gray-200);
  font-size: 0.9rem;
}

.preview-step-num {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--blue-600);
  color: var(--white);
  display: grid;
  place-items: center;
  font-size: 0.8rem;
  font-weight: 700;
  flex-shrink: 0;
}

.preview-step.done .preview-step-num {
  background: #16a34a;
}

/* Sections */
section {
  padding: 80px 0;
}

.section-header {
  text-align: center;
  max-width: 640px;
  margin: 0 auto 48px;
}

.section-header h2 {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  margin: 0 0 12px;
  letter-spacing: -0.02em;
}

.section-header p {
  margin: 0;
  color: var(--gray-500);
  font-size: 1.05rem;
}

.section-alt {
  background: var(--blue-50);
}

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

.feature-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: box-shadow 0.2s, border-color 0.2s;
}

.feature-card:hover {
  border-color: var(--blue-100);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--blue-50);
  color: var(--blue-600);
  display: grid;
  place-items: center;
  font-size: 1.4rem;
  margin-bottom: 16px;
}

.feature-card h3 {
  margin: 0 0 8px;
  font-size: 1.1rem;
}

.feature-card p {
  margin: 0;
  color: var(--gray-500);
  font-size: 0.925rem;
}

/* Workflow */
.workflow-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  counter-reset: step;
}

.workflow-item {
  position: relative;
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
  border: 1px solid var(--gray-200);
  text-align: center;
}

.workflow-item::before {
  counter-increment: step;
  content: counter(step);
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  margin: 0 auto 14px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue-500), var(--blue-700));
  color: var(--white);
  font-weight: 700;
  font-size: 0.95rem;
}

.workflow-item h3 {
  margin: 0 0 8px;
  font-size: 1rem;
}

.workflow-item p {
  margin: 0;
  font-size: 0.875rem;
  color: var(--gray-500);
}

/* Requirements */
.req-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.req-box {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 28px;
  border: 1px solid var(--gray-200);
}

.req-box h3 {
  margin: 0 0 16px;
  color: var(--blue-700);
  font-size: 1.05rem;
}

.req-box ul {
  margin: 0;
  padding-left: 20px;
  color: var(--gray-700);
}

.req-box li {
  margin-bottom: 8px;
}

.req-box li:last-child {
  margin-bottom: 0;
}

/* Download */
.download-card {
  max-width: 720px;
  margin: 0 auto;
  background: linear-gradient(135deg, var(--blue-700), var(--blue-500));
  border-radius: var(--radius-lg);
  padding: 48px 40px;
  text-align: center;
  color: var(--white);
  box-shadow: var(--shadow-lg);
}

.download-card h2 {
  margin: 0 0 12px;
  font-size: 1.75rem;
}

.download-card > p {
  margin: 0 0 28px;
  opacity: 0.9;
}

.download-card .btn-primary {
  background: var(--white);
  color: var(--blue-700);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.15);
}

.download-card .btn-primary:hover {
  color: var(--blue-800);
}

.download-info {
  margin-top: 24px;
  font-size: 0.875rem;
  opacity: 0.85;
}

.download-info code {
  background: rgba(255, 255, 255, 0.15);
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.8rem;
}

/* FAQ */
.faq-list {
  max-width: 760px;
  margin: 0 auto;
}

.faq-item {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-item summary {
  padding: 18px 22px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  font-size: 1.25rem;
  color: var(--blue-600);
  font-weight: 400;
}

.faq-item[open] summary::after {
  content: "−";
}

.faq-item p {
  margin: 0;
  padding: 0 22px 18px;
  color: var(--gray-500);
  font-size: 0.925rem;
}

/* Footer */
.site-footer {
  background: var(--gray-900);
  color: rgba(255, 255, 255, 0.75);
  padding: 48px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand .logo {
  color: var(--white);
  margin-bottom: 12px;
}

.footer-brand p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.7;
}

.footer-col h4 {
  color: var(--white);
  margin: 0 0 14px;
  font-size: 0.95rem;
}

.footer-col ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-col li {
  margin-bottom: 8px;
}

.footer-col a {
  color: rgba(255, 255, 255, 0.65);
  font-size: 0.9rem;
}

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

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.5);
}

/* Responsive */
@media (max-width: 960px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .hero-visual {
    order: -1;
    max-width: 480px;
    margin-inline: auto;
  }

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

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

@media (max-width: 720px) {
  .nav-toggle {
    display: block;
  }

  .nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--white);
    border-bottom: 1px solid var(--gray-200);
    padding: 12px 16px 20px;
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.25s, opacity 0.25s;
  }

  .nav.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav a {
    padding: 12px 8px;
    border-bottom: 1px solid var(--gray-100);
  }

  .nav .btn {
    margin-top: 12px;
    width: 100%;
  }

  .features-grid,
  .workflow-steps,
  .req-grid,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  section {
    padding: 56px 0;
  }

  .download-card {
    padding: 36px 24px;
  }
}