/* ========== Reset & Base ========== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
img, svg, video { max-width: 100%; height: auto; }
:root {
  --bg: #F8FAFC;
  --card: #FFFFFF;
  --border: rgba(37,99,235,0.1);
  --text: #1F2937;
  --text-dim: #6B7280;
  --blue: #2563EB;
  --blue-light: #EFF6FF;
  --green: #10B981;
  --green-light: #ECFDF5;
  --amber: #F59E0B;
  --violet: #7C3AED;
  --pink: #DB2777;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 4px 16px rgba(0,0,0,0.08);
  --shadow-lg: 0 10px 34px rgba(0,0,0,0.10);
  --font: 'Inter', -apple-system, sans-serif;
  --maxw: 1200px;
  --transition: 0.22s ease;
}
html { scroll-behavior: smooth; }
body { font-family: var(--font); background: var(--bg); color: var(--text); -webkit-font-smoothing: antialiased; overflow-x: hidden; }

/* ========== Header ========== */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,0.94);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow 0.25s ease, background 0.25s ease;
}
.site-header.scrolled {
  box-shadow: 0 2px 20px rgba(0,0,0,0.09);
  background: rgba(255,255,255,0.98);
}
.header-inner {
  max-width: var(--maxw); margin: 0 auto;
  padding: 0 24px; height: 64px;
  display: flex; align-items: center; justify-content: space-between;
}

/* Logo */
.logo { display: flex; align-items: center; gap: 8px; text-decoration: none; }
.logo-dot {
  width: 9px; height: 9px; border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--violet));
  box-shadow: 0 0 10px rgba(37,99,235,0.45);
  flex-shrink: 0;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.logo:hover .logo-dot { transform: scale(1.35); box-shadow: 0 0 16px rgba(37,99,235,0.6); }
.logo-icon-img { width: 26px; height: 26px; border-radius: 7px; object-fit: contain; flex-shrink: 0; }
.logo-text {
  font-family: 'JetBrains Mono', 'Courier New', monospace;
  font-size: 1.1rem; font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
  transition: color 0.2s;
}
.logo:hover .logo-text { color: var(--blue); }

/* Nav links */
.nav-links { display: flex; align-items: center; gap: 2px; }
.nav-link {
  position: relative; padding: 8px 14px;
  text-decoration: none; color: var(--text-dim);
  font-size: 0.9rem; font-weight: 500;
  border-radius: 8px;
  transition: color 0.2s, background 0.2s;
  white-space: nowrap;
}
.nav-link::after {
  content: ''; position: absolute;
  bottom: 4px; left: 50%; transform: translateX(-50%);
  width: 0; height: 2.5px;
  background: var(--blue); border-radius: 2px;
  transition: width 0.25s ease;
}
.nav-link:hover { color: var(--blue); background: var(--blue-light); }
.nav-link:hover::after { width: 60%; }
.nav-link.active { color: var(--blue); font-weight: 600; }
.nav-link.active::after { width: 60%; }

/* CTA button */
.nav-cta {
  margin-left: 12px; padding: 9px 20px;
  background: var(--blue); color: #fff;
  text-decoration: none; border-radius: 10px;
  font-size: 0.88rem; font-weight: 600;
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
  box-shadow: 0 2px 10px rgba(37,99,235,0.3);
  white-space: nowrap;
}
.nav-cta:hover { background: #1d4ed8; transform: translateY(-1px); box-shadow: 0 4px 16px rgba(37,99,235,0.4); }
.nav-cta:active { transform: translateY(0); }

/* Hamburger */
.hamburger {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: 1.5px solid var(--border);
  border-radius: 8px; padding: 9px 10px;
  cursor: pointer; transition: var(--transition);
}
.hamburger:hover { background: var(--blue-light); border-color: var(--blue); }
.hamburger span {
  display: block; width: 20px; height: 2px;
  background: var(--text); border-radius: 2px;
  transition: transform 0.28s ease, opacity 0.2s ease;
  transform-origin: center;
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile Drawer */
.mobile-drawer {
  display: none; /* shown by JS */
  flex-direction: column; gap: 2px;
  padding: 10px 16px 16px;
  border-top: 1px solid var(--border);
  background: #fff;
  animation: drawerSlide 0.22s ease;
}
@keyframes drawerSlide {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}
.mob-link {
  padding: 12px 16px; border-radius: 10px;
  text-decoration: none; color: var(--text);
  font-size: 0.95rem; font-weight: 500;
  transition: background 0.15s, color 0.15s;
}
.mob-link:hover { background: var(--blue-light); color: var(--blue); }
.mob-link.active { background: var(--blue-light); color: var(--blue); font-weight: 600; }
.mob-cta {
  margin-top: 8px; padding: 13px 16px;
  background: var(--blue); color: #fff;
  border-radius: 10px; text-decoration: none;
  font-size: 0.95rem; font-weight: 600; text-align: center;
  transition: background 0.2s;
}
.mob-cta:hover { background: #1d4ed8; }

/* ========== Hero ========== */
.hero { background: linear-gradient(135deg, #1e3a8a 0%, #6d28d9 50%, #db2777 100%); padding: 64px 24px 48px; text-align: center; }
.hero-badge { display: inline-block; background: rgba(255,255,255,0.18); color: #fff; padding: 6px 16px; border-radius: 20px; font-size: 0.82rem; font-weight: 600; margin-bottom: 18px; border: 1px solid rgba(255,255,255,0.25); }
.hero-title { font-size: clamp(2rem, 5vw, 3.2rem); font-weight: 800; color: #fff; margin-bottom: 14px; line-height: 1.15; }
.gradient-text { background: linear-gradient(90deg, #67e8f9, #a5f3fc, #fde68a); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.hero-sub { color: rgba(255,255,255,0.8); font-size: 1.1rem; max-width: 520px; margin: 0 auto 32px; }

/* Search */
.search-bar { position: relative; max-width: 560px; margin: 0 auto 28px; }
.search-icon { position: absolute; left: 18px; top: 50%; transform: translateY(-50%); font-size: 1.1rem; pointer-events: none; }
#searchInput { width: 100%; padding: 16px 52px 16px 48px; border: none; border-radius: 14px; font-size: 1rem; font-family: var(--font); background: rgba(255,255,255,0.97); color: var(--text); box-shadow: 0 8px 32px rgba(0,0,0,0.2); outline: none; transition: var(--transition); }
#searchInput:focus { box-shadow: 0 8px 32px rgba(0,0,0,0.3), 0 0 0 3px rgba(255,255,255,0.4); }
.clear-btn { position: absolute; right: 16px; top: 50%; transform: translateY(-50%); background: none; border: none; color: var(--text-dim); font-size: 1rem; cursor: pointer; padding: 4px 8px; border-radius: 6px; }
.clear-btn:hover { background: #f3f4f6; color: var(--text); }

/* Stats */
.stats-bar { display: flex; align-items: center; justify-content: center; gap: 0; background: rgba(255,255,255,0.12); border: 1px solid rgba(255,255,255,0.2); border-radius: 14px; max-width: 460px; margin: 0 auto; padding: 10px 0; }
.stat-item { display: flex; flex-direction: column; align-items: center; padding: 4px 28px; }
.stat-num { font-size: 1.4rem; font-weight: 800; color: #fff; line-height: 1; }
.stat-label { font-size: 0.72rem; color: rgba(255,255,255,0.65); text-transform: uppercase; letter-spacing: 0.05em; margin-top: 2px; }
.stat-divider { width: 1px; height: 36px; background: rgba(255,255,255,0.2); }

/* ========== Filter Toolbar (slim sticky bar) ========== */
.filter-toolbar {
  position: sticky; top: 64px; z-index: 89;
  background: rgba(255,255,255,0.96);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.filter-toolbar-inner {
  max-width: var(--maxw); margin: 0 auto;
  padding: 10px 24px;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  flex-wrap: wrap;
}
.ftb-left { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.ftb-right { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }

/* Trigger buttons */
.ftb-trigger {
  display: flex; align-items: center; gap: 5px;
  padding: 8px 14px; border-radius: 10px;
  border: 1.5px solid var(--border);
  background: var(--bg); color: var(--text);
  font-size: 0.85rem; font-weight: 500;
  cursor: pointer; font-family: var(--font);
  transition: border-color 0.2s, background 0.2s, box-shadow 0.2s;
  white-space: nowrap;
}
.ftb-trigger:hover { border-color: var(--blue); background: var(--blue-light); color: var(--blue); }
.ftb-trigger.open { border-color: var(--blue); background: var(--blue-light); color: var(--blue); box-shadow: 0 0 0 3px rgba(37,99,235,0.1); }
.ftb-trigger.has-filter { border-color: var(--blue); background: var(--blue); color: #fff; }
.ftb-trigger.has-filter:hover { background: #1d4ed8; }
.ftb-active-label { font-size: 0.75rem; font-weight: 700; max-width: 80px; overflow: hidden; text-overflow: ellipsis; }
.ftb-caret { font-size: 0.7rem; margin-left: 2px; transition: transform 0.2s; }
.ftb-trigger.open .ftb-caret { transform: rotate(180deg); }

/* Active pills row */
.active-pills { display: flex; gap: 6px; flex-wrap: wrap; }
.active-pill {
  display: flex; align-items: center; gap: 5px;
  padding: 4px 10px 4px 12px; border-radius: 20px;
  background: #eff6ff; border: 1.5px solid var(--blue);
  color: var(--blue); font-size: 0.75rem; font-weight: 600;
  animation: pillPop 0.18s ease;
}
@keyframes pillPop { from { transform: scale(0.8); opacity: 0; } to { transform: scale(1); opacity: 1; } }
.active-pill button { background: none; border: none; color: var(--blue); font-size: 0.8rem; cursor: pointer; padding: 0 0 0 2px; line-height: 1; }
.active-pill button:hover { color: #1d4ed8; }

/* Result count + reset */
.result-count { font-size: 0.83rem; color: var(--text-dim); white-space: nowrap; }
.reset-btn {
  padding: 7px 14px; border-radius: 8px;
  border: 1.5px solid var(--border); background: var(--bg);
  color: var(--text-dim); font-size: 0.82rem; font-weight: 500;
  cursor: pointer; font-family: var(--font); transition: var(--transition);
  white-space: nowrap;
}
.reset-btn:hover { background: #fee2e2; border-color: #ef4444; color: #ef4444; }
.reset-btn.hidden { opacity: 0; pointer-events: none; }

/* ========== Floating Popover Panels ========== */
.filter-backdrop {
  display: none; position: fixed;
  inset: 0; z-index: 88;
  background: transparent;
}
.filter-backdrop.visible { display: block; }

.filter-panel {
  display: none; /* shown via JS */
  position: absolute; left: 24px; top: calc(100% + 8px);
  z-index: 200;
  background: #fff; border: 1.5px solid var(--border);
  border-radius: 16px; box-shadow: 0 12px 40px rgba(0,0,0,0.13), 0 4px 12px rgba(0,0,0,0.07);
  min-width: 320px; max-width: 480px;
  animation: panelDrop 0.2s cubic-bezier(0.16,1,0.3,1);
  transform-origin: top left;
}
@keyframes panelDrop {
  from { opacity: 0; transform: translateY(-8px) scale(0.97); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}
.filter-panel.open { display: block; }

.fp-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 16px 10px;
  font-size: 0.88rem; font-weight: 700; color: var(--text);
  border-bottom: 1px solid var(--border);
}
.fp-close {
  background: none; border: none; font-size: 1rem;
  color: var(--text-dim); cursor: pointer; padding: 4px 6px;
  border-radius: 6px; transition: background 0.15s;
}
.fp-close:hover { background: #f3f4f6; color: var(--text); }

.fp-chips { display: flex; gap: 8px; flex-wrap: wrap; padding: 14px 16px 16px; }

/* Chips (inside panels) */
.chip {
  padding: 7px 16px; border-radius: 20px;
  border: 1.5px solid var(--border);
  background: var(--bg); color: var(--text-dim);
  font-size: 0.83rem; font-weight: 500;
  cursor: pointer; font-family: var(--font);
  transition: border-color 0.15s, background 0.15s, color 0.15s, transform 0.1s;
}
.chip:hover { border-color: var(--blue); color: var(--blue); background: var(--blue-light); transform: translateY(-1px); }
.chip.active { background: var(--blue); border-color: var(--blue); color: #fff; }
.chip.active:hover { background: #1d4ed8; }

/* ========== Main ========== */
.main-content { max-width: var(--maxw); margin: 0 auto; padding: 40px 24px 80px; }

/* Section Headers */
.courses-section, .platforms-section { margin-bottom: 56px; }
.section-header { margin-bottom: 24px; }
.section-title-wrap { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.section-icon { font-size: 1.5rem; }
.section-title { font-size: 1.55rem; font-weight: 800; color: var(--text); }
.section-badge { background: var(--green-light); color: var(--green); font-size: 0.78rem; font-weight: 700; padding: 3px 10px; border-radius: 20px; border: 1px solid rgba(16,185,129,0.2); }
.section-desc { color: var(--text-dim); font-size: 0.95rem; }

/* ========== Course Grid ========== */
.course-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 20px; }

/* Course Card */
.course-card { background: var(--card); border-radius: var(--radius); border: 1.5px solid var(--border); box-shadow: var(--shadow); overflow: hidden; cursor: pointer; transition: transform var(--transition), box-shadow var(--transition); display: flex; flex-direction: column; }
.course-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--blue); }
.card-platform-bar { display: flex; align-items: center; justify-content: space-between; padding: 12px 16px 10px; border-bottom: 1px solid var(--border); }
.platform-logo { width: 80px; height: 28px; object-fit: contain; }
.free-badge { background: var(--green-light); color: var(--green); font-size: 0.7rem; font-weight: 700; padding: 3px 8px; border-radius: 20px; border: 1px solid rgba(16,185,129,0.25); }
.card-body { padding: 16px; flex: 1; display: flex; flex-direction: column; }
.course-title { font-size: 0.97rem; font-weight: 700; color: var(--text); margin-bottom: 8px; line-height: 1.4; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.course-meta { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 12px; }
.meta-tag { font-size: 0.72rem; padding: 3px 10px; border-radius: 20px; font-weight: 500; }
.tag-level-beginner { background: #ecfdf5; color: #059669; }
.tag-level-intermediate { background: #fffbeb; color: #d97706; }
.tag-level-advanced { background: #fef2f2; color: #dc2626; }
.tag-topic { background: var(--blue-light); color: var(--blue); }
.tag-duration { background: #f5f3ff; color: var(--violet); }
.course-desc { font-size: 0.83rem; color: var(--text-dim); line-height: 1.5; flex: 1; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.card-footer { padding: 12px 16px; border-top: 1px solid var(--border); display: flex; align-items: center; justify-content: space-between; }
.visit-btn { font-size: 0.82rem; font-weight: 600; color: var(--blue); text-decoration: none; display: flex; align-items: center; gap: 4px; }
.visit-btn:hover { color: #1d4ed8; }
.rating { display: flex; align-items: center; gap: 4px; font-size: 0.78rem; color: var(--text-dim); }
.rating .stars { color: #f59e0b; }

/* ========== Platform Grid ========== */
.platform-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 16px; }
.platform-card { background: var(--card); border-radius: var(--radius-sm); border: 1.5px solid var(--border); padding: 20px; cursor: pointer; transition: var(--transition); display: flex; flex-direction: column; align-items: center; gap: 12px; text-align: center; }
.platform-card:hover { border-color: var(--blue); box-shadow: var(--shadow); transform: translateY(-2px); }
.platform-icon { font-size: 2rem; }
.platform-name { font-weight: 700; font-size: 0.95rem; color: var(--text); }
.platform-desc { font-size: 0.78rem; color: var(--text-dim); line-height: 1.4; }
.platform-tag { font-size: 0.7rem; padding: 3px 10px; border-radius: 20px; background: var(--green-light); color: var(--green); font-weight: 600; }

/* ========== Loading & Empty States ========== */
.loading-state { grid-column: 1/-1; display: flex; flex-direction: column; align-items: center; gap: 14px; padding: 60px 0; color: var(--text-dim); }
.spinner { width: 36px; height: 36px; border: 3px solid var(--border); border-top-color: var(--blue); border-radius: 50%; animation: spin 0.8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.no-results { text-align: center; padding: 80px 24px; }
.no-results-icon { font-size: 3.5rem; margin-bottom: 16px; }
.no-results h3 { font-size: 1.4rem; font-weight: 700; margin-bottom: 8px; }
.no-results p { color: var(--text-dim); margin-bottom: 20px; }

/* ========== Update Bar ========== */
.update-bar { position: fixed; bottom: 0; left: 0; right: 0; background: rgba(255,255,255,0.95); backdrop-filter: blur(8px); border-top: 1px solid var(--border); padding: 10px 24px; display: flex; align-items: center; justify-content: center; gap: 16px; font-size: 0.8rem; color: var(--text-dim); z-index: 80; }
.refresh-btn { background: var(--blue); color: #fff; border: none; padding: 6px 16px; border-radius: 8px; font-size: 0.8rem; font-weight: 600; cursor: pointer; transition: var(--transition); font-family: var(--font); }
.refresh-btn:hover { background: #1d4ed8; }
.refresh-btn.spinning { opacity: 0.6; pointer-events: none; }

/* ========== Responsive ========== */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .hamburger { display: flex; }
  .filter-toolbar-inner { gap: 8px; }
  .filter-panel { left: 12px; right: 12px; min-width: unset; max-width: unset; }
  .course-grid { grid-template-columns: 1fr 1fr; }
  .stats-bar { max-width: 100%; }
  .stat-item { padding: 4px 16px; }
}
@media (max-width: 480px) {
  .course-grid { grid-template-columns: 1fr; }
  .platform-grid { grid-template-columns: 1fr 1fr; }
  .ftb-right { width: 100%; justify-content: space-between; }
}