:root {
  --bg: #f6f8fb;
  --panel: #ffffff;
  --panel-soft: #f1f5fb;
  --text: #111827;
  --muted: #667085;
  --faint: #8a95a6;
  --line: rgba(17, 24, 39, 0.09);
  --accent: #2563eb;
  --accent-strong: #1d4ed8;
  --shadow: 0 14px 38px rgba(15, 23, 42, 0.08);
  --sidebar-w: 300px;
  --font-sans: "DM Sans", system-ui, -apple-system, sans-serif;
  --font-display: "Plus Jakarta Sans", var(--font-sans);
  --font-brand: "Sora", var(--font-display);
}

:root[data-theme="dark"] {
  --bg: #0b1020;
  --panel: #111827;
  --panel-soft: #151f33;
  --text: #eef4ff;
  --muted: #a8b3c7;
  --faint: #77849a;
  --line: rgba(226, 232, 240, 0.12);
  --accent: #60a5fa;
  --accent-strong: #93c5fd;
  --shadow: 0 18px 48px rgba(0, 0, 0, 0.28);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  color: var(--text);
  background:
    radial-gradient(circle at 74% 10%, rgba(37, 99, 235, 0.08), transparent 26%),
    linear-gradient(180deg, var(--bg), var(--bg));
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
}

button,
input {
  font: inherit;
}

.learning-shell {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  min-height: 100vh;
}

.learning-sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  border-right: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 90%, transparent);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  padding: 1rem 0.8rem 1.25rem;
}

.sidebar-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  width: 100%;
  min-height: 48px;
  padding: 0.35rem 0.5rem 1rem;
  color: var(--text);
  text-decoration: none;
  font-family: var(--font-brand);
  font-size: 1rem;
  font-weight: 800;
  letter-spacing: -0.025em;
}

.sidebar-brand img {
  width: 34px;
  height: 34px;
  object-fit: contain;
  filter: drop-shadow(0 8px 14px rgba(37, 99, 235, 0.16));
}

.explorer-label {
  margin: 0.35rem 0.5rem 0.75rem;
  color: var(--faint);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.learning-nav {
  display: grid;
  gap: 0.25rem;
}

.learning-nav details {
  border-radius: 12px;
}

.learning-nav summary {
  cursor: pointer;
  list-style: none;
  border-radius: 10px;
  padding: 0.48rem 0.55rem;
  color: var(--text);
  font-weight: 800;
  font-size: 0.92rem;
  transition: background 0.18s ease, color 0.18s ease;
}

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

.learning-nav summary::before {
  content: "›";
  display: inline-block;
  margin-right: 0.35rem;
  color: var(--faint);
  transition: transform 0.18s ease;
}

.learning-nav details[open] summary::before {
  transform: rotate(90deg);
}

.learning-nav summary:hover,
.learning-nav a:hover {
  background: color-mix(in srgb, var(--accent) 11%, transparent);
  color: var(--accent-strong);
}

.learning-nav a {
  display: block;
  margin-left: 1rem;
  border-radius: 9px;
  padding: 0.35rem 0.55rem;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.88rem;
  line-height: 1.35;
  transition: background 0.18s ease, color 0.18s ease, transform 0.18s ease;
}

.learning-nav a:hover {
  transform: translateX(2px);
}

.learning-nav a.is-current {
  position: relative;
  background: color-mix(in srgb, var(--accent) 13%, transparent);
  color: var(--accent-strong);
  font-weight: 800;
}

.learning-nav a.is-current::after {
  content: "";
  position: absolute;
  right: 0.45rem;
  top: 50%;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent) 28%, transparent);
  transform: translateY(-50%);
  animation: active-pulse 1.8s ease-out infinite;
}

.sidebar-note {
  display: grid;
  gap: 0.35rem;
  margin: 1.3rem 0.45rem 0;
  padding: 0.9rem;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--panel-soft);
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.45;
}

.sidebar-note strong {
  color: var(--text);
}

.learning-main {
  position: relative;
  min-width: 0;
  overflow: hidden;
}

.learning-atmosphere {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  opacity: 0.75;
  background:
    radial-gradient(circle at 82% 16%, color-mix(in srgb, var(--accent) 18%, transparent), transparent 19%),
    radial-gradient(circle at 32% 72%, color-mix(in srgb, var(--accent) 10%, transparent), transparent 22%),
    linear-gradient(120deg, transparent 0 58%, color-mix(in srgb, var(--accent) 6%, transparent) 58% 61%, transparent 61% 100%);
  animation: atmosphere-drift 18s ease-in-out infinite alternate;
}

.learning-topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  justify-content: stretch;
  align-items: center;
  gap: 1rem;
  min-height: 56px;
  padding: 0.45rem clamp(1rem, 3vw, 2rem);
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg) 84%, transparent);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

.sidebar-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: var(--panel);
  cursor: pointer;
}

.sidebar-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 5px auto;
  border-radius: 999px;
  background: var(--text);
}

.search-wrap {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: 0.6rem;
  width: min(100%, 860px);
  min-height: 48px;
  padding: 0 0.9rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--panel);
  box-shadow: 0 8px 22px rgba(15, 23, 42, 0.04);
  transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}

.search-wrap:focus-within {
  border-color: color-mix(in srgb, var(--accent) 44%, var(--line));
  box-shadow: 0 16px 34px color-mix(in srgb, var(--accent) 13%, transparent);
  transform: translateY(-1px);
}

.search-wrap svg {
  width: 19px;
  height: 19px;
  fill: var(--faint);
}

.search-wrap input {
  width: 100%;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--text);
  font-size: 0.95rem;
}

.search-wrap input::placeholder {
  color: var(--faint);
}

.theme-toggle {
  justify-self: end;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--panel);
  color: var(--text);
  cursor: pointer;
  box-shadow: var(--shadow);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.18s ease, border-color 0.18s ease;
}

.theme-toggle:hover {
  border-color: color-mix(in srgb, var(--accent) 38%, var(--line));
  transform: translateY(-2px);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

:root[data-theme="light"] .theme-toggle .sun,
:root[data-theme="dark"] .theme-toggle .moon {
  display: none;
}

.learning-hero,
.learning-section {
  width: min(100% - 2rem, 1720px);
  margin-inline: auto;
}

.learning-hero {
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 2rem;
  margin-top: 0.8rem;
  padding: clamp(1.35rem, 3vw, 2rem);
  border: 1px solid var(--line);
  border-radius: 24px;
  background:
    linear-gradient(135deg, color-mix(in srgb, var(--panel) 94%, transparent), color-mix(in srgb, var(--panel-soft) 78%, transparent)),
    radial-gradient(circle at 84% 0%, color-mix(in srgb, var(--accent) 16%, transparent), transparent 34%);
  box-shadow: var(--shadow);
  animation: panel-rise 0.55s ease both;
}

.learning-hero::after {
  content: "";
  position: absolute;
  inset: auto -10% -42% 48%;
  height: 220px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent) 11%, transparent);
  transform: rotate(-12deg);
  animation: ribbon-float 8s ease-in-out infinite alternate;
  pointer-events: none;
}

.kicker {
  margin: 0 0 0.55rem;
  color: var(--accent-strong);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.learning-hero h1 {
  margin: 0;
  max-width: 780px;
  color: var(--text);
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 4rem);
  line-height: 1.05;
  letter-spacing: -0.04em;
}

.learning-hero p:not(.kicker) {
  margin: 1rem 0 0;
  max-width: 670px;
  color: var(--muted);
  font-size: clamp(1rem, 1.4vw, 1.16rem);
  line-height: 1.7;
}

.topic-page {
  width: min(100% - 2rem, 1720px);
  margin: 1.2rem auto 0;
  padding: clamp(1.2rem, 2.4vw, 1.8rem);
  border: 1px solid var(--line);
  border-radius: 22px;
  background:
    linear-gradient(145deg, color-mix(in srgb, var(--panel) 96%, transparent), color-mix(in srgb, var(--panel-soft) 70%, transparent)),
    radial-gradient(circle at 92% 4%, color-mix(in srgb, var(--accent) 15%, transparent), transparent 30%);
  box-shadow: var(--shadow);
  transform-origin: top center;
}

.topic-page.is-switching {
  animation: topic-pop 0.38s cubic-bezier(0.16, 1, 0.3, 1);
}

.topic-header {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 1.5rem;
  margin-bottom: 1.2rem;
}

.topic-header h2 {
  margin: 0;
  color: var(--text);
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3vw, 2.7rem);
  line-height: 1.08;
  letter-spacing: -0.04em;
}

.topic-header p:not(.kicker) {
  margin: 0.8rem 0 0;
  max-width: 780px;
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.7;
}

.topic-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  flex: 0 0 auto;
  padding: 0.68rem 1rem;
  border-radius: 999px;
  background: var(--text);
  color: var(--bg);
  font-weight: 800;
  text-decoration: none;
  transition: transform 0.18s ease, background 0.18s ease;
}

.topic-action:hover {
  background: var(--accent);
  color: #fff;
  transform: translateY(-2px);
}

.topic-layout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.topic-card {
  position: relative;
  overflow: hidden;
  padding: 1rem 1.05rem;
  border: 1px solid var(--line);
  border-radius: 17px;
  background: color-mix(in srgb, var(--panel) 86%, transparent);
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.topic-card::before {
  content: "";
  position: absolute;
  inset: 0;
  opacity: 0;
  background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 9%, transparent), transparent 45%);
  transition: opacity 0.2s ease;
  pointer-events: none;
}

.topic-card:hover {
  border-color: color-mix(in srgb, var(--accent) 26%, var(--line));
  box-shadow: 0 16px 34px rgba(15, 23, 42, 0.08);
  transform: translateY(-3px);
}

.topic-card:hover::before {
  opacity: 1;
}

.topic-wide {
  grid-column: 1 / -1;
}

.topic-card h3 {
  margin: 0 0 0.8rem;
  color: var(--text);
  font-family: var(--font-display);
  font-size: 1.04rem;
  letter-spacing: -0.02em;
}

.topic-card ul,
.topic-card ol {
  margin: 0;
  padding-left: 1.15rem;
  color: var(--muted);
  line-height: 1.72;
}

.topic-card li + li {
  margin-top: 0.45rem;
}

.hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  justify-content: flex-end;
  min-width: min(100%, 320px);
}

.hero-stats span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  min-height: 36px;
  padding: 0.45rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--panel-soft);
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 700;
}

.hero-stats strong {
  color: var(--text);
}

.learning-section {
  margin-top: 1.45rem;
  padding-bottom: 6rem;
}

.section-heading {
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 1rem;
  margin-bottom: 1rem;
}

.section-heading h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.35rem;
  letter-spacing: -0.02em;
}

.result-count {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.module-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 320px), 1fr));
  gap: 1rem;
}

.module-card {
  --tilt-x: 0deg;
  --tilt-y: 0deg;
  --spot-x: 50%;
  --spot-y: 0%;
  position: relative;
  overflow: hidden;
  display: grid;
  grid-template-columns: 94px minmax(0, 1fr);
  gap: 1rem;
  align-items: center;
  min-height: 168px;
  padding: 1.15rem;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--panel);
  box-shadow: var(--shadow);
  transform: perspective(900px) rotateX(var(--tilt-x)) rotateY(var(--tilt-y)) translateY(0);
  transition: transform 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.module-card::before {
  content: "";
  position: absolute;
  inset: 0;
  opacity: 0;
  background:
    radial-gradient(circle at var(--spot-x) var(--spot-y), color-mix(in srgb, var(--accent) 18%, transparent), transparent 34%),
    linear-gradient(135deg, rgba(255, 255, 255, 0.18), transparent 45%);
  transition: opacity 0.18s ease;
  pointer-events: none;
}

.module-card:hover {
  border-color: color-mix(in srgb, var(--accent) 30%, var(--line));
  box-shadow: 0 20px 48px rgba(15, 23, 42, 0.12);
  transform: perspective(900px) rotateX(var(--tilt-x)) rotateY(var(--tilt-y)) translateY(-5px);
}

.module-card:hover::before {
  opacity: 1;
}

.module-number {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  min-height: 126px;
  border: 1px solid color-mix(in srgb, var(--accent) 20%, var(--line));
  border-radius: 14px;
  background: linear-gradient(180deg, color-mix(in srgb, var(--accent) 8%, transparent), transparent);
}

.module-number span {
  color: var(--faint);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.module-number strong {
  color: var(--accent-strong);
  font-family: var(--font-brand);
  font-size: 2rem;
  line-height: 1;
}

.module-card p {
  position: relative;
  z-index: 1;
  margin: 0 0 0.35rem;
  color: var(--accent-strong);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.module-card h3 {
  position: relative;
  z-index: 1;
  margin: 0 0 0.55rem;
  color: var(--text);
  font-family: var(--font-display);
  font-size: 1.08rem;
  letter-spacing: -0.02em;
}

.module-card span,
.module-card small {
  position: relative;
  z-index: 1;
  display: block;
  color: var(--muted);
  font-size: 0.88rem;
}

.module-card small {
  margin-top: 0.5rem;
  color: var(--faint);
}

.empty-state {
  margin: 1rem 0 0;
  padding: 1rem;
  border: 1px dashed var(--line);
  border-radius: 16px;
  color: var(--muted);
  text-align: center;
}

.quick-links {
  position: fixed;
  right: clamp(1rem, 2vw, 1.5rem);
  bottom: clamp(1rem, 2vw, 1.5rem);
  z-index: 30;
  display: grid;
  gap: 0.7rem;
}

.quick-links a {
  width: 48px;
  height: 48px;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--panel);
  color: var(--accent-strong);
  box-shadow: var(--shadow);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.18s ease, background 0.18s ease, color 0.18s ease;
}

.quick-links .quick-link-youtube {
  color: #ff0000;
}

.quick-links .quick-link-email {
  color: #0078d4;
}

.quick-links a:hover {
  color: #fff;
  transform: translateY(-3px);
}

.quick-links .quick-link-youtube:hover {
  background: #ff0000;
}

.quick-links .quick-link-email:hover {
  background: #0078d4;
}

.quick-links svg {
  width: 21px;
  height: 21px;
  fill: currentColor;
}

@media (max-width: 980px) {
  .learning-shell {
    grid-template-columns: 1fr;
  }

  .learning-sidebar {
    position: fixed;
    z-index: 40;
    inset: 0 auto 0 0;
    width: min(82vw, 320px);
    transform: translateX(-104%);
    transition: transform 0.22s ease;
    box-shadow: 24px 0 60px rgba(15, 23, 42, 0.18);
  }

  body.sidebar-open .learning-sidebar {
    transform: translateX(0);
  }

  .learning-topbar {
    grid-template-columns: auto minmax(0, 1fr) auto;
    min-height: 68px;
  }

  .theme-toggle {
    grid-column: auto;
  }

  .sidebar-toggle {
    display: inline-block;
  }

  .learning-hero {
    align-items: stretch;
    flex-direction: column;
  }

  .topic-header {
    flex-direction: column;
  }

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

  .hero-stats {
    justify-content: flex-start;
  }
}

@media (max-width: 640px) {
  .learning-topbar {
    gap: 0.65rem;
    padding-inline: 0.75rem;
  }

  .search-wrap {
    min-height: 44px;
  }

  .learning-hero,
  .learning-section,
  .topic-page {
    width: min(100% - 1rem, 1720px);
  }

  .module-card {
    grid-template-columns: 78px minmax(0, 1fr);
    min-height: 142px;
    padding: 0.9rem;
  }

  .module-number {
    min-height: 104px;
  }

  .module-number strong {
    font-size: 1.55rem;
  }

  .quick-links {
    grid-template-columns: repeat(2, 1fr);
  }
}

@keyframes atmosphere-drift {
  from {
    transform: translate3d(-1%, -1%, 0) scale(1);
  }

  to {
    transform: translate3d(1.5%, 1%, 0) scale(1.04);
  }
}

@keyframes panel-rise {
  from {
    opacity: 0;
    transform: translateY(14px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes ribbon-float {
  from {
    transform: translateX(-3%) rotate(-12deg);
  }

  to {
    transform: translateX(5%) rotate(-9deg);
  }
}

@keyframes active-pulse {
  0% {
    box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent) 32%, transparent);
  }

  100% {
    box-shadow: 0 0 0 10px transparent;
  }
}

@keyframes topic-pop {
  from {
    opacity: 0.45;
    transform: translateY(12px) scale(0.99);
  }

  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.001ms !important;
  }

  .module-card,
  .module-card:hover,
  .topic-card,
  .learning-hero {
    transform: none !important;
  }
}