:root {
  --bg: #f5f7fb;
  --ink: #17202a;
  --muted: #5f6c7b;
  --panel: #ffffff;
  --line: #d8e0ea;
  --blue: #0867d8;
  --cyan: #00a8d8;
  --green: #0f8f6f;
  --amber: #b87300;
  --dark: #111827;
  --shadow: rgba(17, 24, 39, .16);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
}

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

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 68px;
  padding: 14px clamp(18px, 5vw, 64px);
  border-bottom: 1px solid rgba(255, 255, 255, .22);
  background: rgba(11, 17, 29, .72);
  color: #f8fafc;
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  white-space: nowrap;
}

.brand img {
  width: 34px;
  height: 34px;
  border-radius: 8px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(12px, 3vw, 28px);
  color: rgba(248, 250, 252, .82);
  font-size: 14px;
}

.site-nav a:hover {
  color: #ffffff;
}

.hero {
  position: relative;
  min-height: 78vh;
  display: grid;
  align-items: end;
  overflow: hidden;
  background: var(--dark);
  color: #ffffff;
}

.hero-media {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(6, 10, 18, .94), rgba(6, 10, 18, .6) 48%, rgba(6, 10, 18, .28)),
    url("/assets/ddtv-banner.jpg") center / cover no-repeat;
  transform: scale(1.03);
}

.hero-content {
  position: relative;
  width: min(940px, calc(100% - 36px));
  margin: 0 auto;
  padding: 136px 0 86px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--cyan);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .08em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  letter-spacing: 0;
}

h1 {
  margin: 0;
  max-width: 760px;
  font-size: clamp(44px, 7vw, 86px);
  line-height: .98;
}

h2 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(28px, 4vw, 46px);
  line-height: 1.12;
}

h3 {
  margin: 12px 0 8px;
  color: var(--ink);
  font-size: 19px;
}

p {
  color: var(--muted);
  line-height: 1.72;
  overflow-wrap: anywhere;
}

.hero-copy {
  max-width: 690px;
  margin: 22px 0 0;
  color: rgba(248, 250, 252, .86);
  font-size: clamp(18px, 2.4vw, 24px);
}

.hero-actions,
.release-band {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.hero-actions {
  margin-top: 34px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: 8px;
  font-weight: 800;
}

.button.primary {
  background: var(--blue);
  color: #ffffff;
}

.button.ghost {
  border-color: rgba(255, 255, 255, .36);
  color: #ffffff;
}

.section {
  width: min(1180px, calc(100% - 36px));
  margin: 0 auto;
  padding: 72px 0;
}

.section-head {
  max-width: 760px;
  margin-bottom: 28px;
}

.feature-grid,
.privacy-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.feature-grid article,
.privacy-list article {
  min-height: 210px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 14px 40px var(--shadow);
}

.feature-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 28px;
  border-radius: 6px;
  background: #e7f7f3;
  color: var(--green);
  font-weight: 900;
}

.split-band {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 480px);
  gap: 42px;
  align-items: center;
}

.split-band p,
.release-band p {
  max-width: 660px;
}

.remote-panel {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 18px 46px var(--shadow);
}

/* 远程面板是官网示意图，不绑定真实控制接口，避免误触生产 API。 */
.remote-screen {
  position: relative;
  aspect-ratio: 16 / 9;
  border-radius: 8px;
  background: #151f2e;
  overflow: hidden;
}

.remote-dot {
  position: absolute;
  width: 18px;
  height: 18px;
  left: 56%;
  top: 44%;
  border: 3px solid #ffffff;
  border-radius: 50%;
  background: var(--cyan);
}

.remote-line {
  position: absolute;
  left: 26px;
  right: 26px;
  height: 12px;
  border-radius: 999px;
  background: #d7e2ee;
  opacity: .78;
}

.remote-line.short {
  top: 30px;
  right: 42%;
  background: var(--cyan);
}

.remote-line:not(.short):not(.medium) {
  bottom: 58px;
}

.remote-line.medium {
  bottom: 30px;
  right: 26%;
  background: #f4c15d;
}

.remote-actions {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 8px;
  margin-top: 12px;
}

.remote-actions span {
  min-height: 32px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.privacy-band {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.privacy-list {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.release-band {
  justify-content: space-between;
}

.release-band .button {
  flex: 0 0 auto;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 24px clamp(18px, 5vw, 64px);
  border-top: 1px solid var(--line);
  color: var(--muted);
}

.site-footer span:first-child {
  color: var(--ink);
  font-weight: 900;
}

@media (max-width: 900px) {
  .site-header {
    position: absolute;
    align-items: flex-start;
    flex-direction: column;
  }

  .site-nav {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 2px;
  }

  .hero-content {
    padding-top: 164px;
  }

  .feature-grid,
  .privacy-list,
  .split-band {
    grid-template-columns: 1fr;
  }

  .release-band {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (max-width: 560px) {
  .hero {
    min-height: 84vh;
  }

  .hero-content {
    width: calc(100% - 48px);
  }

  .hero-copy {
    font-size: 17px;
  }

  .hero-actions .button,
  .release-band .button {
    width: 100%;
  }

  .section {
    padding: 52px 0;
  }

  .remote-actions {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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