/* ============================================================
   SwapxLearn – Global Design System
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;600;700;800;900&family=Fira+Code:wght@400;500&display=swap');

/* ── CSS Variables ─────────────────────────────────────── */
:root {
  --bg-base:      #0a0f1e;
  --bg-surface:   #111827;
  --bg-card:      rgba(255,255,255,0.04);
  --bg-card-hover:rgba(255,255,255,0.08);
  --border:       rgba(255,255,255,0.08);
  --border-hover: rgba(255,255,255,0.18);

  --primary:      #4f8ef7;
  --primary-glow: rgba(79,142,247,0.35);
  --secondary:    #a259ff;
  --accent-green: #39ff14;
  --accent-gold:  #f7d94f;
  --accent-red:   #ff6b6b;
  --accent-orange:#ffb347;

  --text-primary:  #f0f4ff;
  --text-secondary:#8a95b0;
  --text-muted:    #4a5568;

  --radius-sm:  8px;
  --radius-md:  14px;
  --radius-lg:  20px;
  --radius-xl:  28px;

  --shadow-sm:  0 2px 8px rgba(0,0,0,0.3);
  --shadow-md:  0 8px 32px rgba(0,0,0,0.5);
  --shadow-glow:0 0 30px var(--primary-glow);

  --transition: 0.25s cubic-bezier(.4,0,.2,1);
  --nav-height: 70px;
}

/* ── Reset & Base ──────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  line-height: 1.6;
}

h1,h2,h3,h4,h5,h6 {
  font-family: 'Outfit', sans-serif;
  line-height: 1.2;
  color: var(--text-primary);
}

a { text-decoration: none; color: inherit; }
img { max-width: 100%; }
ul { list-style: none; }

::selection {
  background: var(--primary);
  color: #fff;
}

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-base); }
::-webkit-scrollbar-thumb { background: var(--primary); border-radius: 3px; }

/* ── Navigation ─────────────────────────────────────────── */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  padding: 0 5%;
  background: rgba(10,15,30,0.85);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}

.navbar.scrolled {
  background: rgba(10,15,30,0.98);
  box-shadow: var(--shadow-md);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: 'Outfit', sans-serif;
  font-size: 1.5rem;
  font-weight: 800;
}

.nav-logo .logo-swap { color: var(--primary); }
.nav-logo .logo-x    { color: var(--secondary); }
.nav-logo .logo-learn{ color: var(--text-primary); }
.nav-logo .logo-dot  {
  width: 8px; height: 8px;
  background: var(--accent-green);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%,100% { transform: scale(1); opacity:1; }
  50%      { transform: scale(1.5); opacity:0.6; }
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2px;
  margin: 0 auto;
}

.nav-links a {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition);
  position: relative;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
  background: var(--bg-card);
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -2px; left: 50%;
  transform: translateX(-50%);
  width: 20px; height: 2px;
  background: var(--primary);
  border-radius: 1px;
}

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

.btn-nav-quiz {
  padding: 8px 20px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: #fff;
  border-radius: 50px;
  font-size: 0.875rem;
  font-weight: 600;
  transition: all var(--transition);
  box-shadow: 0 0 15px var(--primary-glow);
}

.btn-nav-quiz:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 25px var(--primary-glow);
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}
.hamburger:hover { background: var(--bg-card); }
.hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text-primary);
  border-radius: 1px;
  transition: all var(--transition);
}

/* ── Buttons ─────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 50px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  font-family: 'Inter', sans-serif;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: #fff;
  box-shadow: 0 4px 20px var(--primary-glow);
}
.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 30px var(--primary-glow);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
}
.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-hover);
  transform: translateY(-2px);
}

.btn-ghost {
  background: transparent;
  color: var(--primary);
  border: 1px solid var(--primary);
}
.btn-ghost:hover {
  background: rgba(79,142,247,0.1);
  transform: translateY(-2px);
}

.btn-sm { padding: 8px 18px; font-size: 0.85rem; }
.btn-lg { padding: 16px 40px; font-size: 1.1rem; }

/* ── Cards ──────────────────────────────────────────────── */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg,rgba(79,142,247,0.05),rgba(162,89,255,0.05));
  opacity: 0;
  transition: opacity var(--transition);
}

.card:hover {
  border-color: var(--border-hover);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}
.card:hover::before { opacity: 1; }

/* ── Badge ──────────────────────────────────────────────── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.badge-beginner  { background: rgba(57,255,20,0.12);  color: var(--accent-green); border: 1px solid rgba(57,255,20,0.25); }
.badge-intermediate { background: rgba(79,142,247,0.12); color: var(--primary);   border: 1px solid rgba(79,142,247,0.25); }
.badge-advanced  { background: rgba(162,89,255,0.12); color: var(--secondary);    border: 1px solid rgba(162,89,255,0.25); }
.badge-quiz      { background: rgba(247,217,79,0.12); color: var(--accent-gold);  border: 1px solid rgba(247,217,79,0.25); }
.badge-project   { background: rgba(255,107,107,0.12);color: var(--accent-red);   border: 1px solid rgba(255,107,107,0.25); }

/* ── Section & Layout ─────────────────────────────────── */
.section {
  padding: 80px 5%;
}

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-label {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--primary);
  margin-bottom: 12px;
  padding: 6px 16px;
  background: rgba(79,142,247,0.1);
  border-radius: 50px;
  border: 1px solid rgba(79,142,247,0.2);
}

.section-title {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 800;
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 540px;
  margin: 0 auto;
}

.gradient-text {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.grid-auto { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px; }

/* ── Page wrapper ─────────────────────────────────────── */
.page-content {
  padding-top: var(--nav-height);
  min-height: 100vh;
}

/* ── Tags ─────────────────────────────────────────────── */
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  display: inline-block;
  padding: 4px 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 50px;
  font-size: 0.75rem;
  color: var(--text-secondary);
  transition: all var(--transition);
}
.tag:hover {
  background: rgba(79,142,247,0.1);
  border-color: var(--primary);
  color: var(--primary);
  cursor: pointer;
}

/* ── Course Card ─────────────────────────────────────── */
.course-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: all var(--transition);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 16px;
  position: relative;
  overflow: hidden;
  text-decoration: none;
}

.course-card::after {
  content:'';
  position:absolute;
  bottom:0; left:0; right:0;
  height: 3px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.course-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-6px);
  box-shadow: 0 20px 60px rgba(0,0,0,0.4);
}
.course-card:hover::after { transform: scaleX(1); }

.course-icon {
  font-size: 2.5rem;
  width: 60px; height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
}

.course-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 4px;
}

.course-stat {
  display: flex;
  align-items: center;
  gap: 4px;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.course-title {
  font-size: 1.15rem;
  font-weight: 700;
}

.course-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
  flex: 1;
}

/* ── Article Card ────────────────────────────────────── */
.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
  cursor: pointer;
}

.article-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.article-thumb {
  height: 180px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  position: relative;
  overflow: hidden;
}

.article-body {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  flex: 1;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.article-title {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.3;
}

.article-excerpt {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
  flex: 1;
}

/* ── Stat Cards ──────────────────────────────────────── */
.stat-card {
  text-align: center;
  padding: 28px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}

.stat-number {
  font-family: 'Outfit', sans-serif;
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* ── Progress Bar ────────────────────────────────────── */
.progress-bar {
  width: 100%;
  height: 6px;
  background: var(--bg-card);
  border-radius: 3px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 3px;
  transition: width 0.6s ease;
}

/* ── Alert / Notification ────────────────────────────── */
.alert {
  padding: 14px 20px;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 10px;
}

.alert-success { background: rgba(57,255,20,0.1); border: 1px solid rgba(57,255,20,0.25); color: var(--accent-green); }
.alert-error   { background: rgba(255,107,107,0.1); border: 1px solid rgba(255,107,107,0.25); color: var(--accent-red); }
.alert-info    { background: rgba(79,142,247,0.1);  border: 1px solid rgba(79,142,247,0.25);  color: var(--primary); }

/* ── Footer ──────────────────────────────────────────── */
.footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border);
  padding: 60px 5% 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-brand p {
  color: var(--text-secondary);
  font-size: 0.875rem;
  line-height: 1.7;
  margin-top: 12px;
  max-width: 280px;
}

.footer-title {
  font-family: 'Outfit', sans-serif;
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.footer-links li { margin-bottom: 10px; }
.footer-links a  { font-size: 0.875rem; color: var(--text-secondary); transition: color var(--transition); }
.footer-links a:hover { color: var(--primary); }

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 28px;
  border-top: 1px solid var(--border);
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ── Animations ──────────────────────────────────────── */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes shimmer {
  0%   { background-position: -200% 0; }
  100% { background-position:  200% 0; }
}

.animate-fade-in { animation: fadeIn 0.5s ease forwards; }
.animate-up      { animation: fadeInUp 0.6s ease forwards; }

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ── Tabs ────────────────────────────────────────────── */
.tabs {
  display: flex;
  gap: 4px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 4px;
  width: fit-content;
}

.tab-btn {
  padding: 8px 20px;
  border-radius: calc(var(--radius-md) - 4px);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  transition: all var(--transition);
  font-family: 'Inter', sans-serif;
}

.tab-btn.active {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: #fff;
  box-shadow: 0 2px 10px var(--primary-glow);
}
.tab-btn:not(.active):hover { background: var(--bg-card-hover); color: var(--text-primary); }

.tab-panel { display: none; }
.tab-panel.active { display: block; animation: fadeIn 0.3s ease; }

/* ── Hero Glow Effect ────────────────────────────────── */
.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  pointer-events: none;
}

/* ── Search Input ────────────────────────────────────── */
.search-box {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 10px 18px;
  transition: border-color var(--transition);
}

.search-box:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79,142,247,0.15);
}

.search-box input {
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-family: 'Inter', sans-serif;
  font-size: 0.95rem;
  width: 100%;
}

.search-box input::placeholder { color: var(--text-muted); }

/* ── Filter Bar ──────────────────────────────────────── */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

.filter-chip {
  padding: 6px 16px;
  border-radius: 50px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  transition: all var(--transition);
}

.filter-chip:hover,
.filter-chip.active {
  background: rgba(79,142,247,0.15);
  border-color: var(--primary);
  color: var(--primary);
}

/* ── Empty State ─────────────────────────────────────── */
.empty-state {
  text-align: center;
  padding: 80px 20px;
  color: var(--text-secondary);
}
.empty-state .empty-icon { font-size: 4rem; margin-bottom: 16px; }
.empty-state h3 { font-size: 1.3rem; margin-bottom: 8px; color: var(--text-primary); }

/* ── Mobile Responsive ──────────────────────────────── */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .hamburger { display: flex; }

  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: var(--nav-height);
    left: 0; right: 0;
    background: rgba(10,15,30,0.98);
    border-bottom: 1px solid var(--border);
    padding: 20px 5%;
    gap: 4px;
    backdrop-filter: blur(20px);
  }

  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .section { padding: 60px 5%; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .footer-bottom { flex-direction: column; gap: 10px; text-align: center; }
}

@media (max-width: 480px) {
  .section { padding: 50px 4%; }
  .btn-lg { padding: 13px 28px; font-size: 1rem; }
}