/* =========================================================
   CourseHub — Custom Styles
   Design language: "systems console" — a light, technical
   theme built around monospace prompts, signal-teal accents,
   and flag-style category tags (--linux, --networking, ...).
   ========================================================= */

:root {
  /* ---- Color tokens ---- */
  --bg: #f5f8f9;              /* cool light background, not cream */
  --surface: #ffffff;         /* card / panel surface */
  --surface-sunken: #edf2f3;  /* inputs, code blocks */
  --ink: #10201e;             /* primary text, deep ink-teal black */
  --ink-soft: #4d5f5c;        /* secondary text */
  --line: #dbe4e3;            /* hairline borders */
  --signal: #0f8b8d;          /* primary accent — signal teal */
  --signal-dark: #0b6b6d;
  --amber: #f2a93b;           /* secondary accent — amber */
  --amber-dark: #d68f22;
  --danger: #d1495b;          /* used sparingly for "security" tag */

  /* ---- Type ---- */
  --font-display: 'IBM Plex Mono', 'JetBrains Mono', monospace;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* ---- Radii / shadow ---- */
  --radius: 10px;
  --shadow-card: 0 1px 2px rgba(16, 32, 30, 0.04), 0 8px 24px rgba(16, 32, 30, 0.06);
  --shadow-card-hover: 0 4px 10px rgba(16, 32, 30, 0.08), 0 16px 32px rgba(16, 32, 30, 0.10);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
}

h1, h2, h3, h4, .display-font {
  font-family: var(--font-display);
  letter-spacing: -0.02em;
  color: var(--ink);
}

a { color: var(--signal-dark); }
a:hover { color: var(--signal); }

::selection { background: var(--amber); color: var(--ink); }

:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
}

/* =========================================================
   Navbar
   ========================================================= */
.navbar-console {
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  padding-top: 0.85rem;
  padding-bottom: 0.85rem;
}

.brand-mark {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--ink);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.brand-mark .cursor-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--signal);
  box-shadow: 0 0 0 3px rgba(15, 139, 141, 0.15);
}

.navbar-console .nav-link {
  font-family: var(--font-display);
  font-size: 0.92rem;
  color: var(--ink-soft);
  padding: 0.4rem 0.9rem !important;
}

.navbar-console .nav-link:hover,
.navbar-console .nav-link.active {
  color: var(--signal-dark);
}

/* =========================================================
   Hero / Terminal signature element
   ========================================================= */
.hero {
  padding: 4.5rem 0 3rem;
  border-bottom: 1px solid var(--line);
}

.hero h1 {
  font-size: clamp(2rem, 4vw, 2.9rem);
  font-weight: 600;
  margin-bottom: 1rem;
}

.hero p.lede {
  color: var(--ink-soft);
  font-size: 1.1rem;
  max-width: 42ch;
}

.terminal {
  background: #0f1d1c;
  border-radius: var(--radius);
  padding: 1.4rem 1.5rem;
  box-shadow: var(--shadow-card);
  font-family: var(--font-display);
  font-size: 0.92rem;
  color: #d7f2ef;
  overflow: hidden;
}

.terminal .terminal-bar {
  display: flex;
  gap: 6px;
  margin-bottom: 0.9rem;
}

.terminal .terminal-bar span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
  background: #2c3f3d;
}

.terminal .terminal-bar span:nth-child(1) { background: #d1495b; }
.terminal .terminal-bar span:nth-child(2) { background: #f2a93b; }
.terminal .terminal-bar span:nth-child(3) { background: #43b581; }

.terminal-line {
  white-space: pre-wrap;
  min-height: 1.4em;
}

.terminal-line .prompt-symbol { color: #43e6c4; }
.terminal-line .caret {
  display: inline-block;
  width: 8px;
  height: 1em;
  background: #43e6c4;
  vertical-align: -2px;
  animation: blink 1s steps(1) infinite;
}

@keyframes blink {
  50% { opacity: 0; }
}

/* =========================================================
   Search / filter bar
   ========================================================= */
.filter-bar {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin: -2.25rem auto 2.5rem;
  box-shadow: var(--shadow-card);
  position: relative;
  z-index: 2;
}

.filter-bar .prompt-label {
  font-family: var(--font-display);
  color: var(--signal-dark);
  font-size: 0.85rem;
  white-space: nowrap;
}

#courseSearch {
  border: 1px solid var(--line);
  background: var(--surface-sunken);
  font-family: var(--font-display);
  font-size: 0.95rem;
  padding: 0.55rem 0.9rem;
}

#courseSearch:focus {
  background: var(--surface);
  border-color: var(--signal);
  box-shadow: 0 0 0 3px rgba(15, 139, 141, 0.12);
}

.category-chip {
  font-family: var(--font-display);
  font-size: 0.78rem;
  border: 1px solid var(--line);
  background: var(--surface-sunken);
  color: var(--ink-soft);
  border-radius: 999px;
  padding: 0.35rem 0.85rem;
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.category-chip:hover {
  border-color: var(--signal);
  color: var(--signal-dark);
}

.category-chip.active {
  background: var(--ink);
  border-color: var(--ink);
  color: #ffffff;
}

/* =========================================================
   Course cards
   ========================================================= */
.section-label {
  font-family: var(--font-display);
  font-size: 0.85rem;
  color: var(--signal-dark);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.5rem;
}

.course-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
  height: 100%;
}

.course-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--signal);
}

.course-card .thumb-wrap {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: var(--surface-sunken);
}

.course-card .thumb-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.35s ease;
}

.course-card:hover .thumb-wrap img {
  transform: scale(1.06);
}

.course-card .card-body {
  padding: 1.35rem;
}

.course-card .card-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.course-card .card-text {
  color: var(--ink-soft);
  font-size: 0.94rem;
  margin-bottom: 1rem;
}

/* Category tags styled as CLI flags, e.g. --linux */
.tag-flag {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-display);
  font-size: 0.72rem;
  padding: 0.2rem 0.55rem;
  border-radius: 5px;
  margin-right: 0.4rem;
  margin-bottom: 0.6rem;
  letter-spacing: 0.01em;
}

.tag-linux { background: rgba(15, 139, 141, 0.12); color: var(--signal-dark); }
.tag-networking { background: rgba(242, 169, 59, 0.16); color: var(--amber-dark); }
.tag-security { background: rgba(209, 73, 91, 0.12); color: var(--danger); }

/* Level tags — beginner/intermediate/advanced (reuse the same 3 accent colors) */
.tag-beginner { background: rgba(15, 139, 141, 0.12); color: var(--signal-dark); }
.tag-intermediate { background: rgba(242, 169, 59, 0.16); color: var(--amber-dark); }
.tag-advanced { background: rgba(209, 73, 91, 0.12); color: var(--danger); }

.card-topic {
  font-family: var(--font-display);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--ink-soft);
  margin: 0.15rem 0 0.3rem;
}

.card-meta {
  font-family: var(--font-display);
  font-size: 0.78rem;
  color: var(--ink-soft);
  margin-bottom: 0.9rem;
}

.btn-console {
  font-family: var(--font-display);
  font-size: 0.9rem;
  background: var(--ink);
  color: #ffffff;
  border: 1px solid var(--ink);
  border-radius: 6px;
  padding: 0.5rem 1.1rem;
  transition: background 0.15s ease, transform 0.15s ease;
}

.btn-console:hover {
  background: var(--signal-dark);
  border-color: var(--signal-dark);
  color: #fff;
  transform: translateX(2px);
}

.btn-console-outline {
  font-family: var(--font-display);
  font-size: 0.9rem;
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0.5rem 1.1rem;
  transition: all 0.15s ease;
}

.btn-console-outline:hover {
  border-color: var(--signal);
  color: var(--signal-dark);
  background: rgba(15, 139, 141, 0.06);
}

#emptyState {
  display: none;
  text-align: center;
  padding: 3.5rem 1rem;
  color: var(--ink-soft);
  font-family: var(--font-display);
}

/* =========================================================
   Course detail page
   ========================================================= */
.course-hero {
  padding: 2.75rem 0 2rem;
  border-bottom: 1px solid var(--line);
}

.breadcrumb-console {
  font-family: var(--font-display);
  font-size: 0.85rem;
  color: var(--ink-soft);
  margin-bottom: 1rem;
}

.breadcrumb-console a { color: var(--signal-dark); text-decoration: none; }
.breadcrumb-console a:hover { text-decoration: underline; }

.video-frame-wrap {
  position: relative;
  width: 100%;
  padding-top: 56.25%; /* 16:9 */
  background: #0f1d1c;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  margin-bottom: 2rem;
}

.video-frame-wrap iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.module-list {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: module-counter;
}

.module-list li {
  counter-increment: module-counter;
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 0.95rem 0.6rem;
  border-bottom: 1px solid var(--line);
  cursor: pointer;
  border-radius: 6px;
  transition: background 0.15s ease;
}

.module-list li:last-child { border-bottom: none; }

.module-list li:hover {
  background: rgba(15, 139, 141, 0.06);
}

.module-list li:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
}

/* Active / "now playing" lesson */
.module-list li.active {
  background: rgba(15, 139, 141, 0.10);
}

.module-list li.active .module-title {
  color: var(--signal-dark);
}

.module-list li.active::before {
  content: "\25B6"; /* play triangle */
  background: var(--signal);
  color: #fff;
  font-size: 0.7rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.module-list li::before {
  content: counter(module-counter, decimal-leading-zero);
  font-family: var(--font-display);
  color: var(--signal-dark);
  font-size: 0.85rem;
  background: rgba(15, 139, 141, 0.10);
  border-radius: 5px;
  padding: 0.25rem 0.5rem;
  flex-shrink: 0;
  width: 1.9rem;
  height: 1.6rem;
  box-sizing: content-box;
  text-align: center;
}

/* Prev / Next lesson controls under the video */
.module-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 2rem;
}

.module-nav button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

#activeModuleMeta {
  font-family: var(--font-display);
  font-size: 0.82rem;
  color: var(--ink-soft);
}

#moduleDocLink {
  margin-bottom: 1.5rem;
}

.module-list .module-title {
  font-weight: 600;
  margin-bottom: 0.15rem;
}

.module-list .module-meta {
  font-family: var(--font-display);
  font-size: 0.78rem;
  color: var(--ink-soft);
}

.sidebar-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow-card);
}

.sidebar-panel h4 {
  font-size: 1rem;
  margin-bottom: 1rem;
}

.sidebar-panel dl {
  margin: 0;
}

.sidebar-panel dt {
  font-family: var(--font-display);
  font-size: 0.78rem;
  color: var(--ink-soft);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.sidebar-panel dd {
  margin-bottom: 0.9rem;
  font-weight: 500;
}

/* =========================================================
   Footer
   ========================================================= */
.footer-console {
  background: var(--ink);
  color: rgba(255, 255, 255, 0.65);
  padding: 2.5rem 0;
  margin-top: 4rem;
  font-size: 0.9rem;
}

.footer-console .brand-mark { color: #fff; }
.footer-console a { color: rgba(255, 255, 255, 0.8); }
.footer-console a:hover { color: var(--amber); }

/* =========================================================
   About / Support page
   ========================================================= */
.profile-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 2.25rem;
  box-shadow: var(--shadow-card);
}

.profile-avatar {
  width: 88px;
  height: 88px;
  border-radius: 50%;
  background: var(--ink);
  color: #fff;
  font-family: var(--font-display);
  font-size: 1.7rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.positioning-line {
  font-family: var(--font-display);
  font-size: 0.95rem;
  color: var(--signal-dark);
  background: rgba(15, 139, 141, 0.08);
  border-left: 3px solid var(--signal);
  padding: 0.65rem 1rem;
  border-radius: 0 6px 6px 0;
  margin: 1.25rem 0;
}

.about-section-heading {
  font-family: var(--font-display);
  font-size: 0.95rem;
  color: var(--signal-dark);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 2.25rem;
  margin-bottom: 0.9rem;
}

.about-section-heading i { font-size: 1rem; }

.feature-grid {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.9rem;
}

.feature-grid li {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  background: var(--surface-sunken);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.85rem 1rem;
  font-size: 0.92rem;
}

.feature-grid i {
  color: var(--signal-dark);
  font-size: 1.1rem;
  margin-top: 0.1rem;
  flex-shrink: 0;
}

.bio-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.bio-list li {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.95rem;
}

.bio-list li:last-child { border-bottom: none; }

.bio-list i {
  color: var(--signal-dark);
  width: 1.2rem;
  flex-shrink: 0;
  text-align: center;
}

.skill-chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.skill-chip {
  font-family: var(--font-display);
  font-size: 0.78rem;
  background: var(--surface-sunken);
  border: 1px solid var(--line);
  color: var(--ink-soft);
  border-radius: 999px;
  padding: 0.35rem 0.85rem;
}

.social-proof-line {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.92rem;
  color: var(--ink-soft);
  padding: 0.4rem 0;
}

.social-proof-line i { color: var(--amber-dark); }

.vision-block {
  background: linear-gradient(135deg, rgba(15, 139, 141, 0.06), rgba(242, 169, 59, 0.06));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.4rem 1.5rem;
}

.about-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  background: var(--ink);
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
  margin-top: 2.5rem;
  color: #fff;
}

.about-cta p {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1rem;
}

/* Support / donate card */
.support-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.75rem;
  box-shadow: var(--shadow-card);
}

.support-card h4 {
  font-size: 1.05rem;
  margin-bottom: 0.4rem;
}

.support-used-for {
  font-size: 0.85rem;
  color: var(--ink-soft);
  background: var(--surface-sunken);
  border-radius: 6px;
  padding: 0.6rem 0.8rem;
  margin: 0.9rem 0 1.4rem;
}

.qr-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.9rem;
  margin-bottom: 0.5rem;
}

.qr-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  text-align: center;
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  background: var(--surface-sunken);
}

.qr-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(16, 32, 30, 0.08);
}

.qr-card img {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  display: block;
}

.qr-card .qr-label {
  font-family: var(--font-display);
  font-size: 0.78rem;
  padding: 0.5rem 0.4rem;
  font-weight: 600;
}

.qr-card.qr-esewa .qr-label { color: #2f6b1f; background: rgba(96, 187, 70, 0.12); }
.qr-card.qr-khalti .qr-label { color: #5c2d91; background: rgba(92, 45, 145, 0.1); }

.support-note {
  font-size: 0.82rem;
  color: var(--ink-soft);
  margin-top: 0.9rem;
  margin-bottom: 0;
}

/* Small footer support widget, shown on every page */
.footer-support {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  margin-top: 2rem;
  padding-top: 1.5rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

.footer-support span {
  font-family: var(--font-display);
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.6);
  margin-right: 0.25rem;
}

.footer-support a {
  font-family: var(--font-display);
  font-size: 0.82rem;
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 999px;
  padding: 0.3rem 0.8rem;
  text-decoration: none;
}

.footer-support a:hover {
  border-color: var(--amber);
  color: var(--amber);
}

/* =========================================================
   Motion / accessibility
   ========================================================= */
@media (prefers-reduced-motion: reduce) {
  .course-card,
  .course-card .thumb-wrap img,
  .btn-console,
  .btn-console-outline {
    transition: none !important;
  }
  .terminal-line .caret { animation: none; }
}

@media (max-width: 767.98px) {
  .hero { padding: 3rem 0 2rem; }
  .filter-bar { margin-top: 1.5rem; }
  .feature-grid { grid-template-columns: 1fr; }
  .qr-row { grid-template-columns: 1fr 1fr; }
  .about-cta { flex-direction: column; align-items: flex-start; }
}