:root {
  --bg: #070708;
  --surface: #101012;
  --surface-2: #18181b;
  --border: #27272a;
  --text: #fafafa;
  --muted: #a1a1aa;
  --accent: #38bdf8;
  --accent-dim: #0ea5e9;
  --accent-glow: rgba(56, 189, 248, 0.22);
  --radius: 12px;
  --font: "Segoe UI", system-ui, -apple-system, sans-serif;
}

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

html,
body {
  height: 100%;
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

.screen[hidden] {
  display: none !important;
}

.login-screen {
  min-height: 100%;
  display: grid;
  place-items: center;
  padding: 24px;
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, var(--accent-glow), transparent),
    var(--bg);
}

.login-card {
  width: min(400px, 100%);
  padding: 36px 32px;
  border-radius: calc(var(--radius) + 4px);
  background: linear-gradient(145deg, var(--surface) 0%, var(--surface-2) 100%);
  border: 1px solid var(--border);
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.45);
}

.login-brand-row {
  display: flex;
  justify-content: center;
  margin: 0 0 20px;
}

.login-logo {
  display: block;
  max-width: min(260px, 100%);
  width: 100%;
  height: auto;
}

.login-brand {
  margin: 0 0 8px;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-align: center;
}

.login-hint {
  margin: 0 0 28px;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.5;
}

.login-welcome-line {
  text-align: center;
}

.login-form label {
  display: block;
  margin-bottom: 16px;
}

.login-form label span {
  display: block;
  font-size: 0.8rem;
  color: var(--muted);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.login-form input {
  width: 100%;
  padding: 12px 14px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 1rem;
}

.login-form input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.error {
  color: #f87171;
  font-size: 0.9rem;
  margin: 0 0 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border: none;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: transform 0.12s ease, box-shadow 0.12s ease, background 0.12s;
}

.btn:active {
  transform: scale(0.98);
}

.btn-primary {
  width: 100%;
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent-dim) 100%);
  color: #020617;
  box-shadow: 0 4px 24px var(--accent-glow);
}

.btn-primary:hover {
  box-shadow: 0 6px 32px rgba(56, 189, 248, 0.35);
}

.btn-wide {
  width: auto;
  min-width: 280px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 16px 28px;
  border-radius: 14px;
  font-size: 0.85rem;
}

.btn-chevron {
  font-size: 1.25rem;
  line-height: 0;
  margin-left: 4px;
  opacity: 0.9;
}

.app-layout {
  display: grid;
  grid-template-columns: min(320px, 38vw) 1fr;
  min-height: 100vh;
}

.mobile-to-overview {
  display: none;
}

/* Obere Leiste nur im Mobil-Video-Modus sichtbar */
.mobile-watch-bar {
  display: none;
}

.sidebar-mobile-backdrop {
  display: none;
}

@media (max-width: 840px) {
  .app-layout {
    display: block;
    min-height: 100dvh;
    min-height: 100vh;
    position: relative;
    padding-bottom: env(safe-area-inset-bottom, 0);
  }

  /* ——— Phase 1: nur Kursliste (Vollbild) ——— */
  .app-layout.app--mobile-browse .main {
    display: none !important;
  }

  .app-layout.app--mobile-browse .sidebar-mobile-backdrop {
    display: none !important;
  }

  .app-layout.app--mobile-browse .sidebar {
    position: relative;
    width: 100%;
    min-height: 100dvh;
    min-height: 100vh;
    max-height: none;
    border-right: none;
    border-bottom: none;
    padding: max(12px, env(safe-area-inset-top)) 16px
      max(20px, env(safe-area-inset-bottom));
    padding-left: max(16px, env(safe-area-inset-left));
    padding-right: max(16px, env(safe-area-inset-right));
  }

  .app-layout.app--mobile-browse .sections {
    flex: 1 1 auto;
    max-height: none;
    min-height: 0;
    margin-top: 8px;
    -webkit-overflow-scrolling: touch;
  }

  /* ——— Phase 2: nur Video + Leiste (Schublade für Liste) ——— */
  .app-layout.app--mobile-watch .mobile-watch-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 10px 14px;
    padding-top: max(10px, env(safe-area-inset-top));
    padding-left: max(14px, env(safe-area-inset-left));
    padding-right: max(14px, env(safe-area-inset-right));
    margin: 0 0 8px;
    position: sticky;
    top: 0;
    z-index: 45;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
  }

  .app-layout.app--mobile-watch .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: min(86vw, 320px);
    max-width: 100%;
    z-index: 100;
    /* Touches gehen zum Video — geschlossene Schublade darf nicht darüber liegen (sonst „toter“ Play). */
    pointer-events: none;
    transform: translateX(-105%);
    transition: transform 0.28s ease;
    border-right: 1px solid var(--border);
    border-bottom: none;
    box-shadow: 8px 0 40px rgba(0, 0, 0, 0.45);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    padding-top: max(16px, env(safe-area-inset-top));
    padding-bottom: max(24px, env(safe-area-inset-bottom));
  }

  .app-layout.app--mobile-watch .sidebar.sidebar--drawer-open {
    transform: translateX(0);
    pointer-events: auto;
  }

  .app-layout.app--mobile-watch .sidebar-reset-btn {
    display: none;
  }

  .app-layout.app--mobile-watch .mobile-to-overview {
    display: block;
    width: 100%;
    margin: 4px 0 10px;
    padding: 12px 14px;
    border-radius: 10px;
    border: 1px solid var(--border);
    background: var(--surface-2);
    color: var(--accent);
    font-family: inherit;
    font-size: 0.82rem;
    font-weight: 700;
    cursor: pointer;
    text-align: center;
    -webkit-tap-highlight-color: rgba(56, 189, 248, 0.2);
  }

  .app-layout.app--mobile-browse .mobile-to-overview {
    display: none;
  }

  .app-layout.app--mobile-watch .sidebar-mobile-backdrop {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 90;
    background: rgba(0, 0, 0, 0.5);
    border: none;
    padding: 0;
    margin: 0;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
  }

  .app-layout.app--mobile-watch .sidebar-mobile-backdrop[hidden] {
    display: none !important;
  }

  .app-layout.app--mobile-watch .main {
    position: relative;
    z-index: 2;
    display: flex;
    flex-direction: column;
    width: 100%;
    min-width: 0;
    min-height: 100dvh;
    min-height: 100vh;
    padding: 0 14px 20px;
    padding-left: max(14px, env(safe-area-inset-left));
    padding-right: max(14px, env(safe-area-inset-right));
    padding-bottom: max(20px, env(safe-area-inset-bottom));
    gap: 14px;
    box-sizing: border-box;
  }

  .app-layout.app--mobile-watch .main-head {
    padding-top: 0;
  }

  .mobile-drawer-btn {
    flex: 0 0 auto;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    padding: 0;
    border: none;
    border-radius: 10px;
    background: linear-gradient(180deg, var(--accent) 0%, var(--accent-dim) 100%);
    color: #020617;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
  }

  .mobile-drawer-btn:active {
    transform: scale(0.97);
  }

  .mobile-drawer-btn-bars {
    display: flex;
    flex-direction: column;
    gap: 5px;
    width: 20px;
  }

  .mobile-drawer-btn-bars span {
    display: block;
    height: 2.5px;
    background: currentColor;
    border-radius: 1px;
  }

  .mobile-bar-reset {
    flex: 0 1 auto;
    max-width: 52%;
    padding: 10px 12px;
    border-radius: 10px;
    border: 1px solid rgba(248, 113, 113, 0.45);
    background: transparent;
    color: #f87171;
    font-family: inherit;
    font-size: 0.78rem;
    font-weight: 600;
    line-height: 1.25;
    cursor: pointer;
    text-align: center;
    -webkit-tap-highlight-color: rgba(248, 113, 113, 0.15);
  }

  .mobile-bar-reset.sidebar-reset-btn--armed,
  .mobile-bar-reset.mobile-bar-reset--armed {
    border-color: #f87171;
    background: rgba(248, 113, 113, 0.2);
    color: #fecaca;
    font-weight: 800;
  }

  .app-layout.app--mobile-watch .player-shell {
    max-height: min(52dvh, calc(100vw * 9 / 16));
    max-width: 100%;
    margin: 0 auto;
    width: 100%;
    flex: 0 0 auto;
    min-height: 180px;
    touch-action: manipulation;
  }

  .app-layout.app--mobile-watch .player {
    touch-action: manipulation;
  }

  .lesson-title {
    font-size: 1.2rem;
    line-height: 1.3;
    word-break: break-word;
  }

  .lesson-meta {
    font-size: 0.82rem;
  }

  .actions {
    width: 100%;
  }

  .actions .btn-wide {
    width: 100%;
    min-width: 0;
    max-width: none;
    padding: 16px 20px;
    font-size: 0.88rem;
  }

  .player-toolbar {
    flex-direction: column;
    align-items: stretch;
  }

  .player-toolbar .player-quality-wrap {
    min-width: 0;
  }

  .player-quality-select {
    width: 100%;
    min-height: 48px;
    font-size: 1rem;
  }

  .btn-tv {
    width: 100%;
    min-height: 48px;
    justify-content: center;
    font-size: 0.9rem;
    white-space: normal;
    text-align: center;
  }

  .lesson-item {
    min-height: 48px;
    padding: 14px 12px;
    font-size: 0.92rem;
    -webkit-tap-highlight-color: rgba(56, 189, 248, 0.2);
  }

  .lesson-idx {
    flex: 0 0 36px;
    width: 36px;
    height: 36px;
    font-size: 0.8rem;
  }

  .lesson-text {
    font-size: 0.92rem;
  }

  .lesson-sub {
    font-size: 0.78rem;
  }

  .section summary {
    padding: 14px 12px;
    font-size: 0.9rem;
    min-height: 48px;
  }

  .sidebar-folder-btn,
  .sidebar-reset-btn {
    font-size: 0.8rem;
    min-height: 44px;
  }
}

.sidebar {
  background: var(--surface);
  border-right: 1px solid var(--border);
  padding: 20px 18px 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.back-link {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.85rem;
  align-self: flex-start;
}

.back-link:hover {
  color: var(--accent);
}

.sidebar-brand {
  display: flex;
  justify-content: center;
  align-items: center;
}

.sidebar-logo {
  display: block;
  max-width: 160px;
  width: 100%;
  height: auto;
  opacity: 0.96;
}

.user-welcome {
  margin: -4px 0 0;
  padding: 0 4px;
  font-size: 0.88rem;
  color: var(--muted);
  line-height: 1.45;
  text-align: center;
}

.course-title {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  line-height: 1.25;
}

.progress-wrap {
  margin-top: 4px;
}

.progress-bar {
  height: 4px;
  border-radius: 2px;
  background: var(--surface-2);
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  width: 0%;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent-dim), var(--accent));
  transition: width 0.35s ease;
}

.progress-label {
  margin: 8px 0 0;
  font-size: 0.8rem;
  color: var(--muted);
}

.sections {
  flex: 1;
  overflow-y: auto;
  margin-top: 8px;
  padding-right: 4px;
}

.section {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  margin-bottom: 10px;
  overflow: hidden;
}

.section summary {
  list-style: none;
  cursor: pointer;
  padding: 12px 14px;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  user-select: none;
}

.section--complete summary {
  color: var(--accent);
}

.section--locked {
  opacity: 0.52;
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  margin-bottom: 10px;
  padding: 12px 14px 14px;
}

.section--placeholder {
  opacity: 0.92;
  border-style: dashed;
}

.section--placeholder summary {
  cursor: default;
  color: var(--muted);
}

.section--placeholder .section-sub {
  color: #71717a;
}

.section--optional-filled {
  border-color: rgba(56, 189, 248, 0.2);
}

.placeholder-hint {
  margin: 0;
  padding: 12px 12px 14px;
  font-size: 0.8rem;
  line-height: 1.45;
  color: var(--muted);
  list-style: none;
}

.sidebar-folder-btn {
  margin-top: 14px;
  width: 100%;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px dashed var(--border);
  background: transparent;
  color: var(--muted);
  font-family: inherit;
  font-size: 0.75rem;
  cursor: pointer;
  line-height: 1.35;
}

.sidebar-folder-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.sidebar-reset-btn {
  margin-top: 8px;
  width: 100%;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid rgba(248, 113, 113, 0.35);
  background: transparent;
  color: #f87171;
  font-family: inherit;
  font-size: 0.75rem;
  cursor: pointer;
  line-height: 1.35;
  transition: border-color 0.15s, background 0.15s, color 0.15s;
}

.sidebar-reset-btn:hover {
  border-color: #f87171;
  background: rgba(248, 113, 113, 0.08);
}

.sidebar-reset-btn.sidebar-reset-btn--armed {
  border-color: #f87171;
  background: rgba(248, 113, 113, 0.18);
  color: #fecaca;
  font-weight: 700;
}

.section-head {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.section-title-text {
  font-weight: 700;
  line-height: 1.25;
}

.section-sub {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--muted);
  text-transform: none;
  letter-spacing: 0;
}

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

.section summary::after {
  content: "";
  width: 8px;
  height: 8px;
  border-right: 2px solid var(--muted);
  border-bottom: 2px solid var(--muted);
  transform: rotate(45deg);
  transition: transform 0.2s ease;
}

.section[open] summary::after {
  transform: rotate(-135deg);
  margin-top: 4px;
}

.section ul {
  margin: 0;
  padding: 0 6px 10px;
  list-style: none;
}

.lesson-item {
  display: block;
  width: 100%;
  text-align: left;
  padding: 10px 10px;
  margin: 2px 0;
  border: none;
  border-radius: 8px;
  background: transparent;
  color: var(--muted);
  font-family: inherit;
  font-size: 0.86rem;
  cursor: pointer;
  line-height: 1.35;
}

.lesson-row {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  width: 100%;
}

.lesson-idx {
  flex: 0 0 28px;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  font-size: 0.72rem;
  font-weight: 800;
  background: var(--surface-2);
  color: var(--muted);
  line-height: 1;
}

.lesson-item--progress .lesson-idx {
  background: rgba(56, 189, 248, 0.12);
  color: var(--accent);
  box-shadow: inset 0 0 0 1px rgba(56, 189, 248, 0.35);
}

.lesson-item--done .lesson-idx {
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent-dim) 100%);
  color: #020617;
}

.lesson-idx--file-num {
  background: rgba(56, 189, 248, 0.16) !important;
  color: var(--accent) !important;
  font-weight: 900;
  box-shadow: inset 0 0 0 1px rgba(56, 189, 248, 0.4);
}

.lesson-main {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.lesson-text {
  color: inherit;
  font-weight: 600;
  font-size: 0.86rem;
}

.lesson-item--todo .lesson-text {
  font-weight: 500;
}

.lesson-sub {
  font-size: 0.72rem;
  color: var(--muted);
  font-weight: 500;
}

.lesson-item:hover {
  background: var(--surface-2);
  color: var(--text);
}

.lesson-item.is-active {
  background: rgba(56, 189, 248, 0.12);
  color: var(--accent);
  box-shadow: inset 0 0 0 1px rgba(56, 189, 248, 0.25);
}

.lesson-item.is-done .lesson-text {
  color: var(--text);
}

.main {
  display: flex;
  flex-direction: column;
  padding: 24px 28px 32px;
  gap: 20px;
  min-width: 0;
}

.main-head {
  padding-top: 4px;
}

.lesson-title {
  margin: 0;
  font-size: clamp(1.25rem, 2.5vw, 1.75rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.lesson-heading-num {
  display: inline-block;
  margin-right: 0.35em;
  padding: 0.15em 0.5em;
  border-radius: 8px;
  font-size: 0.68em;
  font-weight: 800;
  vertical-align: middle;
  line-height: 1.2;
  background: rgba(56, 189, 248, 0.22);
  color: var(--accent);
  box-shadow: inset 0 0 0 1px rgba(56, 189, 248, 0.35);
}

.lesson-heading-rest {
  vertical-align: middle;
  font-weight: 700;
}

.lesson-meta {
  margin: 10px 0 0;
  font-size: 0.88rem;
  color: var(--muted);
  line-height: 1.45;
}

.lesson-meta strong {
  color: var(--text);
  font-weight: 600;
}

.lesson-meta .lesson-meta-status {
  color: var(--accent);
}

.finish-hint {
  margin: 12px 0 0;
  padding: 12px 14px;
  border-radius: var(--radius);
  border: 1px solid rgba(56, 189, 248, 0.35);
  background: rgba(56, 189, 248, 0.08);
  color: var(--text);
  font-size: 0.9rem;
  line-height: 1.45;
}

.player-shell {
  position: relative;
  border-radius: calc(var(--radius) + 4px);
  overflow: hidden;
  background: #000;
  border: 1px solid var(--border);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
  aspect-ratio: 16 / 9;
  max-height: min(72vh, 900px);
}

.player-shell[data-empty="true"] .player {
  opacity: 0.35;
  pointer-events: none;
}

.player-shell[data-empty="true"] .mobile-play-overlay {
  display: none !important;
}

.mobile-play-overlay {
  display: none;
}

@media (max-width: 840px) {
  .app-layout.app--mobile-watch .mobile-play-overlay:not([hidden]) {
    display: flex !important;
    position: absolute;
    inset: 0;
    z-index: 4;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.4);
    pointer-events: auto;
    border-radius: inherit;
  }

  .mobile-play-overlay-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 10px;
    min-width: 160px;
    min-height: 120px;
    padding: 20px 28px;
    border: none;
    border-radius: 16px;
    background: linear-gradient(180deg, var(--accent) 0%, var(--accent-dim) 100%);
    color: #020617;
    font-family: inherit;
    font-size: 1rem;
    font-weight: 800;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    cursor: pointer;
    box-shadow: 0 12px 40px var(--accent-glow);
    -webkit-tap-highlight-color: transparent;
  }

  .mobile-play-overlay-btn:active {
    transform: scale(0.98);
  }

  .mobile-play-overlay-icon {
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 14px 0 14px 24px;
    border-color: transparent transparent transparent #020617;
    margin-left: 6px;
  }

  .mobile-play-overlay-text {
    font-size: 0.82rem;
  }
}

.player {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  background: #000;
}

.player-shell::after {
  content: "";
  pointer-events: none;
  position: absolute;
  inset: 0;
  border-radius: inherit;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.04);
}

.player-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 16px;
  margin-top: 12px;
}

.player-toolbar .player-quality-wrap {
  flex: 1 1 auto;
  min-width: min(260px, 100%);
  margin-top: 0;
}

.player-quality-wrap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 16px;
  padding: 10px 14px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--surface);
}

.player-quality-label {
  font-size: 0.8rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.player-quality-select {
  min-width: min(220px, 100%);
  padding: 8px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  font: inherit;
  font-size: 0.95rem;
  cursor: pointer;
}

.player-quality-select:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.player-quality-select option {
  background: var(--surface-2);
  color: var(--text);
}

.btn-tv {
  flex: 0 0 auto;
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: border-color 0.15s, background 0.15s;
}

.btn-tv:hover {
  border-color: var(--accent);
  background: var(--surface);
}

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