:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --text: #1f2430;
  --muted: #667085;
  --primary: #1250e6;
  --primary-dark: #0d46d0;
  --border: #e8eaf2;
  --shadow-soft: 0 6px 18px rgba(41, 47, 76, 0.06);
  --theme-bg: rgba(37, 211, 102, 0.08);
  --theme-border: rgba(37, 211, 102, 0.24);
  --theme-text: #166534;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
}

body {
  min-height: 100vh;
}

body.has-video-modal {
  overflow: hidden;
}

a,
button {
  color: inherit;
  font: inherit;
}

a {
  text-decoration: none;
}

.tutorials-shell {
  min-height: 100vh;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 24;
  padding: 18px 16px 14px;
  background:
    radial-gradient(circle at top right, rgba(18, 80, 230, 0.16), transparent 32%),
    linear-gradient(180deg, #ffffff 0%, #f7f8fd 100%);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  display: grid;
  gap: 14px;
}

.topbar__nav {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
  align-items: center;
  gap: 10px;
}

.back-link {
  justify-self: start;
  appearance: none;
  border: none;
  background: transparent;
  padding: 0;
  color: var(--primary-dark);
  font-weight: 800;
  cursor: pointer;
}

.brand--centered {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-width: 0;
}

.brand__logo {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  box-shadow: 0 10px 24px rgba(18, 80, 230, 0.18);
  flex-shrink: 0;
}

.brand__name {
  font-size: 18px;
  font-weight: 800;
  white-space: nowrap;
}

.title-strip {
  padding: 14px 16px;
  border-radius: 18px;
  background: #eceff3;
  border: 1px solid #dde3eb;
}

.title-strip h1 {
  margin: 0;
  color: var(--primary-dark);
  font-size: 22px;
  line-height: 1.1;
}

.tutorials-main {
  padding: 18px 16px 118px;
  display: grid;
  gap: 18px;
}

.intro-card,
.tutorials-layout,
.video-panel {
  border: 1px solid var(--border);
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.95);
  box-shadow: var(--shadow-soft);
}

.intro-card {
  padding: 18px;
}

.intro-card__eyebrow {
  margin: 0 0 8px;
  color: var(--primary-dark);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.intro-card h2 {
  margin: 0;
  font-size: 26px;
  line-height: 1.12;
}

.tutorials-layout {
  padding: 16px;
  display: grid;
  gap: 16px;
}

.tutorial-list {
  display: grid;
  gap: 12px;
}

.tutorial-card {
  width: 100%;
  border: 1px solid var(--theme-border);
  border-radius: 20px;
  background: var(--theme-bg);
  color: var(--theme-text);
  cursor: pointer;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: 12px;
  padding: 14px;
  text-align: left;
}

.tutorial-card span {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  background: #0f8d2d;
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
}

.tutorial-card strong {
  font-size: 18px;
  line-height: 1.2;
}

.tutorial-card.is-active {
  border-color: rgba(18, 80, 230, 0.36);
  box-shadow: 0 0 0 4px rgba(18, 80, 230, 0.08);
}

.video-panel {
  padding: 16px;
  display: grid;
  gap: 14px;
}

.video-panel h2 {
  margin: 0;
  color: var(--primary-dark);
  font-size: 22px;
  line-height: 1.15;
}

.video-frame {
  width: 100%;
  max-width: 420px;
  aspect-ratio: 9 / 16;
  margin: 0 auto;
  overflow: hidden;
  border-radius: 22px;
  background: #111827;
  box-shadow: 0 16px 40px rgba(15, 23, 42, 0.18);
}

.video-frame iframe {
  width: 100%;
  height: 100%;
  border: 0;
  display: block;
}

.video-panel__close {
  display: none;
}

.bottom-nav {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  transform: none;
  width: 100%;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 2px;
  padding: 10px 12px calc(10px + env(safe-area-inset-bottom));
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 24px 24px 0 0;
  background: rgba(35, 48, 70, 0.96);
  backdrop-filter: blur(14px);
  box-shadow: 0 -10px 28px rgba(20, 24, 38, 0.18);
  z-index: 30;
}

.bottom-nav__item {
  appearance: none;
  border: none;
  background: transparent;
  color: rgba(255, 255, 255, 0.72);
  min-height: 58px;
  border-radius: 16px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, transform 0.15s ease;
  position: relative;
}

.bottom-nav__item:hover,
.bottom-nav__item.is-active {
  background: rgba(255, 255, 255, 0.06);
  color: #fff;
}

.bottom-nav__icon {
  width: 22px;
  height: 22px;
  display: inline-flex;
}

.bottom-nav__icon svg {
  width: 100%;
  height: 100%;
  display: block;
}

.bottom-nav__label {
  font-size: 11px;
  line-height: 1;
}

.bottom-nav__menu-wrap {
  position: relative;
  display: flex;
  width: 100%;
}

.bottom-nav__menu-wrap .bottom-nav__item {
  width: 100%;
}

.bottom-nav__menu {
  position: absolute;
  right: 0;
  bottom: calc(100% + 12px);
  min-width: 220px;
  display: grid;
  gap: 6px;
  padding: 10px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 20px;
  background: rgba(35, 48, 70, 0.98);
  box-shadow: 0 18px 38px rgba(20, 24, 38, 0.22);
  backdrop-filter: blur(16px);
}

.bottom-nav__menu[hidden] {
  display: none !important;
}

.bottom-nav__menu-divider {
  height: 1px;
  background: rgba(255, 255, 255, 0.08);
}

.bottom-nav__menu-item {
  appearance: none;
  display: block;
  border: none;
  width: 100%;
  text-align: left;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.06);
  color: #f8fafc;
  padding: 14px;
  font-weight: 700;
  cursor: pointer;
}

.bottom-nav__menu-item:hover,
.bottom-nav__menu-item--current {
  background: rgba(255, 255, 255, 0.1);
  color: #f8fafc;
}

.bottom-nav__menu-item--danger {
  color: #fecaca;
}

@media (max-width: 640px) {
  .topbar__nav {
    grid-template-columns: auto minmax(0, 1fr) auto;
  }

  .brand--centered {
    justify-self: center;
  }

  .brand__name {
    display: inline;
    font-size: 14px;
  }

  .intro-card h2 {
    font-size: 22px;
  }
}

@media (max-width: 767px) {
  .video-panel {
    position: fixed;
    inset: 0;
    z-index: 80;
    padding: max(18px, env(safe-area-inset-top)) 16px max(18px, env(safe-area-inset-bottom));
    border: 0;
    border-radius: 0;
    background: #ffffff;
    display: none;
    grid-template-rows: auto minmax(0, 1fr) auto;
    align-content: stretch;
    gap: 16px;
    overflow: auto;
  }

  .video-panel.is-open {
    display: grid;
  }

  .video-panel h2 {
    font-size: 22px;
  }

  .video-frame {
    align-self: center;
    width: min(100%, 430px);
    max-width: none;
    max-height: calc(100vh - 150px);
  }

  .video-panel__close {
    appearance: none;
    border: none;
    border-radius: 16px;
    background: var(--primary);
    color: #ffffff;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 54px;
    padding: 14px 18px;
    font-weight: 800;
    font-size: 17px;
    position: sticky;
    bottom: 0;
  }
}

@media (min-width: 768px) {
  .tutorials-shell {
    max-width: 980px;
    margin: 0 auto;
  }

  .topbar {
    padding: 18px 24px 14px;
    border-bottom-left-radius: 28px;
    border-bottom-right-radius: 28px;
  }

  .tutorials-main {
    padding: 24px 24px 132px;
  }

  .tutorials-layout {
    grid-template-columns: minmax(260px, 0.9fr) minmax(280px, 1.1fr);
    align-items: start;
  }
}