:root {
  color-scheme: dark;
  --bg: #0b1120;
  --bg-alt: rgba(15, 23, 42, 0.7);
  --surface: rgba(30, 41, 59, 0.55);
  --surface-hover: rgba(51, 65, 85, 0.65);
  --text: #f8fafc;
  --text-muted: #94a3b8;
  --primary: #38bdf8;
  --primary-glow: rgba(56, 189, 248, 0.35);
  --accent: #2dd4bf;
  --accent-glow: rgba(45, 212, 191, 0.3);
  --border: rgba(255, 255, 255, 0.08);
  --border-hover: rgba(56, 189, 248, 0.4);
  --danger: #ef4444;
  --purple: #a855f7;
  --radius-sm: 8px;
  --radius: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;
  --shadow: 0 20px 40px -15px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 25px 50px -12px rgba(0, 0, 0, 0.7);
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--bg);
  background-image: 
    radial-gradient(at 0% 0%, rgba(56, 189, 248, 0.12) 0px, transparent 50%),
    radial-gradient(at 100% 100%, rgba(45, 212, 191, 0.1) 0px, transparent 50%);
  background-attachment: fixed;
  color: var(--text);
  line-height: 1.65;
  min-height: 100vh;
}

.container {
  width: min(1240px, calc(100% - 3rem));
  margin: 0 auto;
}

/* Typography */
h1, h2, h3, h4 {
  color: #ffffff;
  font-weight: 700;
  line-height: 1.25;
}

.text-muted { color: var(--text-muted); }
.text-danger { color: var(--danger); }
.small { font-size: 0.85rem; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.4rem;
  border-radius: var(--radius-full);
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  transition: var(--transition);
  text-decoration: none;
}

.btn-sm {
  padding: 0.45rem 1rem;
  font-size: 0.85rem;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #0b1120;
  box-shadow: 0 4px 20px var(--primary-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px var(--primary-glow);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.06);
  color: var(--text);
  border-color: var(--border);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.25);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

.btn-outline:hover {
  background: rgba(56, 189, 248, 0.1);
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-2px);
}

/* Header & Navigation */
.app-header {
  background: rgba(11, 17, 32, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  padding: 1.2rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.8rem;
}

.brand-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #0b1120;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  box-shadow: 0 0 20px var(--primary-glow);
}

.brand-title {
  font-size: 1.3rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.badge-tag {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  background: rgba(56, 189, 248, 0.15);
  color: var(--primary);
  padding: 0.15rem 0.55rem;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(56, 189, 248, 0.3);
}

.brand-subtitle {
  font-size: 0.82rem;
  color: var(--text-muted);
}

.search-input-wrapper {
  position: relative;
  flex-grow: 1;
  max-width: 450px;
}

.search-icon {
  position: absolute;
  left: 1.2rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
}

.search-input {
  width: 100%;
  background: rgba(15, 23, 42, 0.8);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  padding: 0.65rem 1rem 0.65rem 2.8rem;
  color: var(--text);
  font-family: inherit;
  font-size: 0.9rem;
  outline: none;
  transition: var(--transition);
}

.search-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 12px var(--primary-glow);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.8rem;
}

/* Topic Filters Bar */
.nav-tabs-bar {
  background: rgba(15, 23, 42, 0.6);
  border-bottom: 1px solid var(--border);
  padding: 0.6rem 0;
}

.topic-filters {
  display: flex;
  gap: 0.6rem;
  overflow-x: auto;
}

.filter-pill {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 0.45rem 1.1rem;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  white-space: nowrap;
}

.filter-pill:hover,
.filter-pill.active {
  background: var(--primary);
  color: #0b1120;
  border-color: var(--primary);
  box-shadow: 0 4px 15px var(--primary-glow);
}

/* Main Content Layout */
.main-content {
  padding: 2.5rem 0;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.8rem;
}

/* Card System */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  backdrop-filter: blur(16px);
  box-shadow: var(--shadow);
  transition: var(--transition);
}

/* Featured Article Banner */
.featured-banner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin-bottom: 3rem;
  background: linear-gradient(135deg, rgba(30, 41, 59, 0.8), rgba(15, 23, 42, 0.95));
  border: 1px solid var(--border-hover);
  position: relative;
  overflow: hidden;
}

.featured-banner::before {
  content: 'FEATURED ARCHITECTURE ARTICLE';
  position: absolute;
  top: 1.2rem;
  right: 1.8rem;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  color: var(--primary);
  background: rgba(56, 189, 248, 0.12);
  padding: 0.3rem 0.8rem;
  border-radius: var(--radius-full);
  border: 1px solid rgba(56, 189, 248, 0.3);
}

.featured-title {
  font-size: 1.8rem;
  margin: 0.5rem 0 1rem;
}

.article-meta-flex {
  display: flex;
  align-items: center;
  gap: 1.2rem;
  color: var(--text-muted);
  font-size: 0.88rem;
  flex-wrap: wrap;
}

.author-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
  color: var(--text);
}

.avatar-mini {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #0b1120;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 800;
}

.topic-tag {
  font-family: 'Fira Code', monospace;
  font-size: 0.78rem;
  color: var(--accent);
  background: rgba(45, 212, 191, 0.1);
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-sm);
}

/* Articles Grid */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 2rem;
}

.article-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  cursor: pointer;
}

.article-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-hover);
}

.article-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.article-card-title {
  font-size: 1.25rem;
  margin-bottom: 0.8rem;
  line-height: 1.35;
}

.article-card-summary {
  color: var(--text-muted);
  font-size: 0.95rem;
  flex-grow: 1;
  margin-bottom: 1.5rem;
}

.article-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.article-card-actions {
  display: flex;
  gap: 0.8rem;
}

.icon-btn-action {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition);
  font-size: 1rem;
}

.icon-btn-action:hover,
.icon-btn-action.active {
  color: var(--primary);
}

/* Modals */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(11, 17, 32, 0.85);
  backdrop-filter: blur(12px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-card {
  width: min(650px, 100%);
  max-height: 90vh;
  overflow-y: auto;
  background: #0f172a;
  border: 1px solid var(--border-hover);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  position: relative;
  box-shadow: var(--shadow-lg);
  transform: translateY(20px);
  transition: transform 0.3s ease;
}

.modal-lg {
  width: min(850px, 100%);
}

.modal-overlay.active .modal-card {
  transform: translateY(0);
}

.modal-close {
  position: absolute;
  top: 1.2rem;
  right: 1.5rem;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.8rem;
  cursor: pointer;
  transition: var(--transition);
}

.modal-close:hover {
  color: #ffffff;
}

.modal-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.8rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 1.2rem;
}

.modal-header-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: rgba(56, 189, 248, 0.15);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
}

.publish-form {
  display: grid;
  gap: 1.2rem;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.form-group label {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 600;
}

.form-control {
  background: rgba(15, 23, 42, 0.8);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.65rem 1rem;
  color: var(--text);
  font-family: inherit;
  font-size: 0.9rem;
  outline: none;
  transition: var(--transition);
}

.form-control:focus {
  border-color: var(--primary);
  box-shadow: 0 0 12px var(--primary-glow);
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: 0.8rem;
  margin-top: 1.8rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border);
}

/* Reader View Styles */
.reader-header {
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 1.5rem;
}

.reader-title {
  font-size: 2rem;
  margin: 0.8rem 0;
  line-height: 1.25;
}

.reader-body {
  font-size: 1.05rem;
  line-height: 1.75;
  color: #e2e8f0;
}

.reader-body p {
  margin-bottom: 1.5rem;
}

.reader-body h3 {
  font-size: 1.4rem;
  margin: 2rem 0 1rem;
  color: var(--primary);
}

.reader-body code-block,
.code-box {
  background: #090d16;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1.2rem;
  font-family: 'Fira Code', monospace;
  font-size: 0.88rem;
  color: var(--accent);
  overflow-x: auto;
  margin: 1.5rem 0;
  display: block;
  white-space: pre-wrap;
}

.takeaway-box {
  background: rgba(45, 212, 191, 0.08);
  border-left: 4px solid var(--accent);
  padding: 1.2rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.8rem 0;
  font-weight: 500;
}

.reader-footer {
  justify-content: space-between;
}

.reader-actions {
  display: flex;
  gap: 0.8rem;
}

/* Toast Notification */
.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--accent);
  color: #0b1120;
  font-weight: 700;
  padding: 0.8rem 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transform: translateY(20px);
  transition: var(--transition);
  pointer-events: none;
  z-index: 2000;
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive */
@media (max-width: 768px) {
  .header-container {
    flex-direction: column;
    align-items: stretch;
  }
  .search-input-wrapper {
    max-width: 100%;
  }
  .form-row {
    grid-template-columns: 1fr;
  }
}