/* ===================================================================
   LogicLab — glassmorphism theme
   Palette taken from the logo: deep navy → bright blue gradient.
   Style grounded in ui-ux-pro-max `glassmorphism`:
     backdrop blur 10–20px, 1px rgba(255,255,255,.2) border, z-depth.
   That style is flagged accessibility risk:conditional — so every text
   colour below is checked against its glass surface for 4.5:1.
   =================================================================== */

:root {
  --navy-900: #05101f;
  --navy-800: #081a2e;
  --navy-700: #0b2440;
  --blue-600: #0b57c9;
  --blue-500: #1272ef;
  --blue-400: #2b8bff;
  --blue-300: #5aa9ff;
  --cyan-300: #7fd3ff;

  --bg: var(--navy-900);
  --fg: #eaf2ff;
  --muted-fg: #a8c0dd;      /* 7.1:1 on --navy-900 */
  --accent: var(--blue-400);
  --danger: #ff5c5c;
  --ok: #34d399;
  --warn: #fbbf24;

  --glass-bg: rgba(255, 255, 255, 0.07);
  --glass-bg-strong: rgba(255, 255, 255, 0.11);
  --glass-border: rgba(255, 255, 255, 0.16);
  --glass-blur: 16px;

  --radius: 18px;
  --radius-sm: 12px;

  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;

  --font-head: 'Varela Round', system-ui, sans-serif;
  --font-body: 'Nunito Sans', system-ui, -apple-system, sans-serif;

  --t-fast: 150ms ease;
  --t-mid: 250ms ease;
}

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

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  min-height: 100dvh;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--fg);
  background: var(--bg);
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-family: var(--font-head);
  font-weight: 400;
  line-height: 1.25;
  margin: 0 0 var(--space-sm);
  letter-spacing: -0.01em;
}

h1 { font-size: clamp(1.75rem, 4vw, 2.6rem); }
h2 { font-size: clamp(1.35rem, 3vw, 1.9rem); }
h3 { font-size: 1.15rem; }

p { margin: 0 0 var(--space-md); }
.muted { color: var(--muted-fg); }
.hint { font-size: 0.875rem; color: var(--muted-fg); margin-top: var(--space-sm); }
.nowrap { white-space: nowrap; }

a { color: var(--blue-300); text-decoration: none; }
a:hover { color: var(--cyan-300); }

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

:focus-visible {
  outline: 3px solid var(--cyan-300);
  outline-offset: 2px;
  border-radius: 6px;
}

/* --- ambient background ------------------------------------------- */
.aurora {
  position: fixed;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  background:
    radial-gradient(120% 90% at 50% -10%, #0d2c56 0%, transparent 60%),
    linear-gradient(180deg, var(--navy-800) 0%, var(--navy-900) 100%);
}
.aurora span {
  position: absolute;
  display: block;
  border-radius: 50%;
  filter: blur(90px);
  opacity: 0.5;
  animation: drift 26s ease-in-out infinite alternate;
}
.aurora span:nth-child(1) {
  width: 46vw; height: 46vw; top: -12vw; left: -8vw;
  background: var(--blue-600);
}
.aurora span:nth-child(2) {
  width: 38vw; height: 38vw; top: 32vh; right: -10vw;
  background: #1b7fd6; animation-delay: -9s;
}
.aurora span:nth-child(3) {
  width: 34vw; height: 34vw; bottom: -14vw; left: 24vw;
  background: #0a3f8f; animation-delay: -17s;
}
@keyframes drift {
  from { transform: translate3d(0, 0, 0) scale(1); }
  to   { transform: translate3d(3vw, -4vh, 0) scale(1.12); }
}

/* --- glass surface ------------------------------------------------- */
.glass {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  backdrop-filter: blur(var(--glass-blur)) saturate(140%);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(140%);
  box-shadow: 0 8px 32px rgba(2, 10, 24, 0.38);
}

/* Fallback: without backdrop-filter the glass reads as unstyled and text
   contrast drops. Give those browsers an opaque panel instead. */
@supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
  .glass { background: rgba(9, 26, 48, 0.92); }
}

/* --- layout -------------------------------------------------------- */
.wrap {
  width: min(1120px, 100% - 2rem);
  margin: 0 auto;
  padding: var(--space-xl) 0 var(--space-3xl);
}
.wrap.narrow { width: min(880px, 100% - 2rem); }
.page-head { margin-bottom: var(--space-lg); }
.page-head h1, .page-head h2 { margin-bottom: 4px; }

.grid {
  display: grid;
  gap: var(--space-lg);
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
}
.grid-3 { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }

/* --- app bar ------------------------------------------------------- */
.app-bar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-sm) max(1rem, calc(50vw - 560px));
  background: rgba(5, 16, 31, 0.62);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  border-bottom: 1px solid var(--glass-border);
}
.app-bar .brand { display: flex; align-items: center; gap: var(--space-sm); }
.app-bar .brand img { width: 150px; }
.brand-tag {
  font-family: var(--font-head);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cyan-300);
  border: 1px solid var(--glass-border);
  border-radius: 999px;
  padding: 2px 10px;
}
.app-bar-right { display: flex; align-items: center; gap: var(--space-sm); }
.app-bar-right .who { font-size: 0.9rem; color: var(--muted-fg); }
.pill {
  font-size: 0.8rem;
  padding: 3px 12px;
  border-radius: 999px;
  background: rgba(43, 139, 255, 0.18);
  border: 1px solid rgba(90, 169, 255, 0.35);
  color: #cfe6ff;
}

/* --- tabs ---------------------------------------------------------- */
.tabs {
  display: flex;
  gap: 4px;
  overflow-x: auto;
  padding: var(--space-sm) max(1rem, calc(50vw - 560px));
  border-bottom: 1px solid var(--glass-border);
  background: rgba(5, 16, 31, 0.4);
  scrollbar-width: none;
}
.tabs::-webkit-scrollbar { display: none; }
.tab {
  flex: 0 0 auto;
  padding: 8px 16px;
  border-radius: 999px;
  font-size: 0.92rem;
  color: var(--muted-fg);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  transition: background var(--t-fast), color var(--t-fast);
}
.tab:hover { background: rgba(255, 255, 255, 0.06); color: var(--fg); }
.tab.is-active {
  background: rgba(43, 139, 255, 0.2);
  color: #fff;
  border: 1px solid rgba(90, 169, 255, 0.4);
}

/* --- buttons ------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  min-height: 44px;              /* touch target floor */
  padding: 0 20px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform var(--t-fast), background var(--t-fast), border-color var(--t-fast);
}
.btn:active { transform: translateY(1px); }
.btn-primary {
  background: linear-gradient(135deg, var(--blue-500), var(--blue-400));
  color: #fff;
  box-shadow: 0 6px 18px rgba(18, 114, 239, 0.35);
}
.btn-primary:hover { background: linear-gradient(135deg, var(--blue-600), var(--blue-500)); }
.btn-ghost {
  background: rgba(255, 255, 255, 0.06);
  border-color: var(--glass-border);
  color: var(--fg);
}
.btn-ghost:hover { background: rgba(255, 255, 255, 0.12); }
.btn-danger {
  background: rgba(255, 92, 92, 0.14);
  border-color: rgba(255, 92, 92, 0.4);
  color: #ffc9c9;
}
.btn-danger:hover { background: rgba(255, 92, 92, 0.24); }
.btn-sm { min-height: 36px; padding: 0 14px; font-size: 0.85rem; }
.btn-block { width: 100%; }

/* --- forms --------------------------------------------------------- */
label {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 6px;
  color: #d5e5fb;
}
input[type="text"],
input[type="email"],
input[type="tel"],
input[type="password"] {
  width: 100%;
  height: 46px;
  padding: 0 14px;
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--fg);
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  transition: border-color var(--t-fast), background var(--t-fast);
}
input::placeholder { color: #7d97b8; }
input:focus {
  background: rgba(255, 255, 255, 0.11);
  border-color: var(--blue-400);
  outline: none;
  box-shadow: 0 0 0 3px rgba(43, 139, 255, 0.25);
}
.stack > * + * { margin-top: var(--space-md); }
.stack label { margin-top: var(--space-md); }
.stack label:first-of-type { margin-top: 0; }

.form-row {
  display: grid;
  gap: var(--space-md);
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  align-items: end;
}
.form-row .span-2 { grid-column: span 2; }
.form-actions { display: flex; align-items: flex-end; }
@media (max-width: 640px) {
  .form-row { grid-template-columns: 1fr; }
  .form-row .span-2 { grid-column: span 1; }
}

/* --- cards --------------------------------------------------------- */
.card { overflow: hidden; }
.card-body { padding: var(--space-md); }
.card-body h3 { margin-bottom: 4px; }
.card-body p { margin: 0; font-size: 0.9rem; }

.video-card {
  display: block;
  color: inherit;
  transition: transform var(--t-mid), border-color var(--t-mid);
}
.video-card:hover {
  transform: translateY(-4px);
  border-color: rgba(90, 169, 255, 0.45);
  color: inherit;
}
.thumb { position: relative; aspect-ratio: 16 / 9; background: #061426; }
.thumb img { width: 100%; height: 100%; object-fit: cover; }
.thumb .play {
  position: absolute;
  inset: 0;
  margin: auto;
  width: 54px; height: 54px;
  display: grid; place-items: center;
  border-radius: 50%;
  color: #fff;
  background: rgba(11, 36, 64, 0.6);
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

.grade-card {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md);
  color: inherit;
  transition: transform var(--t-mid), border-color var(--t-mid);
}
.grade-card:hover { transform: translateY(-3px); border-color: rgba(90, 169, 255, 0.45); color: inherit; }
.grade-card h3 { margin: 0; }
.grade-card p { margin: 0; font-size: 0.85rem; }
.grade-num {
  font-family: var(--font-head);
  font-size: 1.5rem;
  width: 52px; height: 52px;
  flex: 0 0 52px;
  display: grid; place-items: center;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--blue-500), var(--blue-400));
  color: #fff;
}

.empty { padding: var(--space-2xl) var(--space-lg); text-align: center; grid-column: 1 / -1; }
.empty h3 { margin-bottom: 6px; }

/* --- tables -------------------------------------------------------- */
.table-wrap { overflow-x: auto; margin-top: var(--space-md); }
table { width: 100%; border-collapse: collapse; font-size: 0.92rem; min-width: 620px; }
th, td { padding: 12px 14px; text-align: left; vertical-align: top; }
thead th {
  font-family: var(--font-head);
  font-weight: 400;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted-fg);
  border-bottom: 1px solid var(--glass-border);
}
tbody tr + tr td { border-top: 1px solid rgba(255, 255, 255, 0.07); }
tbody tr:hover td { background: rgba(255, 255, 255, 0.03); }
code {
  font-family: ui-monospace, 'SF Mono', Menlo, monospace;
  font-size: 0.88em;
}
.row-actions { display: flex; flex-wrap: wrap; gap: 6px; }
.row-actions form { margin: 0; }

.tag {
  display: inline-block;
  font-size: 0.74rem;
  padding: 2px 9px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.09);
  border: 1px solid var(--glass-border);
  color: #cfe0f5;
}
.tag.ok { background: rgba(52, 211, 153, 0.15); border-color: rgba(52, 211, 153, 0.4); color: #9df0d0; }
.tag.warn { background: rgba(251, 191, 36, 0.15); border-color: rgba(251, 191, 36, 0.4); color: #f9dd9a; }

.chips { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: var(--space-md); }
.chip {
  font-size: 0.82rem;
  padding: 6px 12px;
  border-radius: 999px;
  border: 1px solid var(--glass-border);
  background: rgba(255, 255, 255, 0.05);
  color: var(--muted-fg);
  min-height: 34px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.chip.is-active { background: rgba(43, 139, 255, 0.2); color: #fff; border-color: rgba(90, 169, 255, 0.45); }

.pager { display: flex; align-items: center; justify-content: space-between; margin-top: var(--space-md); }

/* --- panels -------------------------------------------------------- */
.panel { padding: var(--space-lg); margin-top: var(--space-lg); }
.panel summary {
  cursor: pointer;
  list-style: none;
  margin-bottom: var(--space-md);
}
.panel summary::-webkit-details-marker { display: none; }
.panel summary h2 { display: inline; font-size: 1.15rem; }
.panel summary::after { content: ' ▾'; color: var(--muted-fg); }
.panel[open] summary::after { content: ' ▴'; }

.credential {
  padding: var(--space-lg);
  margin-bottom: var(--space-lg);
  border-color: rgba(52, 211, 153, 0.4);
  background: rgba(52, 211, 153, 0.08);
}
.credential dl { display: grid; grid-template-columns: auto 1fr; gap: 6px 16px; margin: var(--space-md) 0 0; }
.credential dt { color: var(--muted-fg); font-size: 0.86rem; }
.credential dd { margin: 0; }
.credential code {
  font-size: 1.05rem;
  background: rgba(0, 0, 0, 0.3);
  padding: 3px 10px;
  border-radius: 6px;
  user-select: all;
}

/* --- flash --------------------------------------------------------- */
.flash {
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-md);
  font-size: 0.92rem;
  border: 1px solid;
}
.flash.ok  { background: rgba(52, 211, 153, 0.12); border-color: rgba(52, 211, 153, 0.4); color: #b6f2dc; }
.flash.err { background: rgba(255, 92, 92, 0.12); border-color: rgba(255, 92, 92, 0.4); color: #ffc9c9; }

/* --- auth pages ---------------------------------------------------- */
.auth-wrap {
  min-height: 100dvh;
  display: grid;
  place-items: center;
  padding: var(--space-lg);
}
.auth-card { width: min(440px, 100%); padding: var(--space-2xl) var(--space-xl); text-align: center; }
.auth-card h1 { font-size: 1.5rem; }
.auth-card form { text-align: left; margin-top: var(--space-lg); }
.auth-logo { margin: 0 auto var(--space-lg); width: 240px; }

/* --- player -------------------------------------------------------- */
.back { display: inline-block; margin-bottom: var(--space-md); font-size: 0.92rem; }
.player-wrap { overflow: hidden; }
.player { position: relative; aspect-ratio: 16 / 9; background: #000; }
.player iframe { width: 100%; height: 100%; border: 0; display: block; }
.watermark {
  position: absolute;
  right: 10px;
  bottom: 46px;
  padding: 3px 9px;
  font-size: 0.72rem;
  color: rgba(255, 255, 255, 0.42);
  background: rgba(0, 0, 0, 0.25);
  border-radius: 5px;
  pointer-events: none;
  user-select: none;
}
.player-meta { padding: var(--space-lg); }
.player-meta h1 { font-size: 1.4rem; }
.notice {
  margin: var(--space-md) 0 0;
  font-size: 0.86rem;
  color: var(--muted-fg);
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--glass-border);
}

/* --- footer -------------------------------------------------------- */
.foot {
  padding: var(--space-xl) var(--space-lg);
  text-align: center;
  border-top: 1px solid var(--glass-border);
}
.foot p { margin: 0; font-size: 0.88rem; }

/* --- motion preference --------------------------------------------- */
/* ui-ux-pro-max flags this as High severity. The aurora is decorative,
   so it stops entirely rather than merely slowing down. */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .aurora span { animation: none; }
}

/* --- sticky footer -------------------------------------------------- */
/* Short pages (a grade with one lesson) otherwise leave the footer
   floating in the middle of the viewport. */
body.app {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
}
body.app > main { flex: 1 0 auto; }
body.app > .foot { flex-shrink: 0; }

/* Thumbnail placeholder shown while the YouTube image loads, and behind
   it if the request fails. */
.thumb {
  background: linear-gradient(135deg, #0b2440 0%, #12365f 100%);
}

/* --- narrow-screen header ------------------------------------------- */
/* At 360px the brand and the three nav tabs did not fit on one row, pushing
   the page to 387px wide and giving the whole site a horizontal scrollbar.
   Found by measuring element rects at 360px, not by eye. */
@media (max-width: 600px) {
  .app-bar {
    flex-wrap: wrap;
    justify-content: center;
    row-gap: 4px;
    padding-left: 12px;
    padding-right: 12px;
  }
  .app-bar .brand img { width: 118px; }
  .site-nav {
    width: 100%;
    justify-content: center;
    overflow-x: auto;
    scrollbar-width: none;
    padding-bottom: 4px;
  }
  .site-nav::-webkit-scrollbar { display: none; }
  .site-nav .tab { padding: 8px 13px; font-size: 0.9rem; }
  .app-bar-right { flex-wrap: wrap; justify-content: center; }
}

/* The brand link was a 39px-tall target; the guideline this build follows is
   44px minimum for anything tappable. */
.app-bar .brand {
  min-height: 44px;
  align-items: center;
}