:root {
  --bg: rgba(9, 20, 29, 0.78);
  --panel: rgba(10, 26, 37, 0.76);
  --panel-soft: rgba(21, 42, 54, 0.62);
  --line: rgba(208, 236, 241, 0.20);
  --line-strong: rgba(220, 244, 248, 0.34);
  --text: #d7ebef;
  --muted: #91afb6;
  --accent: #b2dce2;
  --accent-soft: rgba(173, 220, 226, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: auto;
}

body {
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;

  color: var(--text);
  font-family: Tahoma, Verdana, Arial, sans-serif;

  background:
    linear-gradient(rgba(4, 13, 21, 0.68), rgba(4, 13, 21, 0.74)),
    url("assets/background.jpg") center / cover no-repeat,
    #07131d;
}

.site {
  width: min(1500px, calc(100% - 36px));
  min-height: calc(100vh - 36px);

  margin: 18px auto;
  padding: 16px;

  border: 1px solid var(--line);
  border-radius: 24px;

  background: var(--bg);

  box-shadow:
    0 24px 70px rgba(0, 0, 0, 0.38),
    inset 0 1px 0 rgba(255, 255, 255, 0.10);
}

.top {
  min-height: 70px;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 2px 10px 14px;
}

.header-gif {
  width: 42px;
  height: 42px;
  object-fit: contain;
  display: block;
}

.brand {
  min-width: 0;
}

.site-name {
  color: var(--text);
  font: 15px Georgia, "Times New Roman", serif;
  letter-spacing: 0.02em;
}

.layout {
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr);
  gap: 14px;
  align-items: stretch;
}

.sidebar,
.content {
  min-width: 0;

  border: 1px solid var(--line);
  border-radius: 18px;

  background: var(--panel);

  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.07),
    0 14px 36px rgba(0, 0, 0, 0.18);
}

.sidebar {
  padding: 13px;
  display: flex;
  flex-direction: column;
}

.side-title {
  margin: 2px 5px 11px;
  color: var(--muted);
  font-size: 11px;
  letter-spacing: 0.04em;
}

.nav {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 7px;
}

.nav-button {
  width: 100%;
  min-width: 0;
  min-height: 40px;

  display: flex;
  align-items: center;
  gap: 9px;

  margin: 0;
  padding: 8px 10px;

  border: 1px solid var(--line);
  border-radius: 10px;

  color: var(--muted);
  background: rgba(255, 255, 255, 0.025);

  font: inherit;
  font-size: 12px;
  text-align: left;

  cursor: pointer;

  transition:
    background 0.12s ease,
    border-color 0.12s ease,
    color 0.12s ease;
}

.nav-icon {
  width: 18px;
  min-width: 18px;
  flex: 0 0 18px;
  text-align: center;
  color: var(--accent);
}

.nav-label {
  min-width: 0;
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}

.nav-button:hover,
.nav-button:focus-visible {
  color: var(--text);
  border-color: var(--line-strong);
  background: rgba(255, 255, 255, 0.05);
  outline: none;
}

.nav-button.active {
  color: var(--text);
  border-color: var(--line-strong);
  background: var(--accent-soft);
}

.content {
  padding: 14px;
  min-height: 620px;
}

.tab-content[hidden] {
  display: none !important;
}

.tab-content.active {
  display: block;
}

.video-wrap {
  width: 100%;
  height: calc(100vh - 175px);
  min-height: 500px;
  max-height: 820px;

  display: flex;
  align-items: center;
  justify-content: center;

  overflow: hidden;

  border: 1px solid var(--line);
  border-radius: 14px;

  background: #050d14;
}

.home-video {
  width: 100%;
  height: 100%;
  display: block;

  object-fit: contain;
  background: #050d14;
}

.placeholder-page {
  min-height: 550px;

  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;

  text-align: center;
}

.placeholder-page h1 {
  margin: 0;
  color: var(--text);
  font: 22px Georgia, "Times New Roman", serif;
  font-weight: normal;
}

.placeholder-page p {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 11px;
}

footer {
  padding: 13px 4px 2px;
  color: var(--muted);
  text-align: center;
  font-size: 10px;
}

footer::first-letter {
  color: var(--accent);
}

@media (max-width: 850px) {
  .site {
    width: calc(100% - 20px);
    min-height: auto;
    margin: 10px auto;
  }

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

  .nav {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .content {
    min-height: 500px;
  }

  .video-wrap {
    height: auto;
    min-height: 0;
    aspect-ratio: 16 / 9;
  }
}

@media (max-width: 560px) {
  .site {
    width: calc(100% - 12px);
    margin: 6px auto;
    padding: 9px;
    border-radius: 18px;
  }

  .top {
    min-height: 60px;
    padding: 3px 7px 11px;
  }

  .header-gif {
    width: 34px;
    height: 34px;
  }

  .site-name {
    font-size: 14px;
  }

  .sidebar,
  .content {
    border-radius: 14px;
  }

  .content {
    padding: 10px;
  }

  .placeholder-page {
    min-height: 330px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .nav-button {
    transition: none;
  }
}