/* ========================================
   Design System & Custom Properties
   ======================================== */
:root {
  /* Colors - Dark Theme (default) */
  --bg-primary: #0a0e17;
  --bg-secondary: #111827;
  --bg-card: #1a2233;
  --bg-card-hover: #1f2b3f;
  --bg-glass: rgba(17, 24, 39, 0.8);
  --border-color: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(255, 255, 255, 0.12);

  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --accent: #38bdf8;
  --accent-hover: #7dd3fc;
  --accent-glow: rgba(56, 189, 248, 0.15);
  --accent-secondary: #a78bfa;
  --accent-tertiary: #fb923c;
  --accent-success: #34d399;
  --accent-danger: #f87171;

  --gradient-hero: linear-gradient(135deg, #0a0e17 0%, #1a1040 40%, #0f2a3d 70%, #0a0e17 100%);
  --gradient-accent: linear-gradient(135deg, #38bdf8, #a78bfa);

  /* Typography */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-display: 'Space Grotesk', 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --section-padding: 6rem 2rem;
  --card-padding: 1.75rem;
  --card-radius: 16px;
  --nav-height: 64px;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  --bg-glass: rgba(255, 255, 255, 0.85);
  --border-color: rgba(0, 0, 0, 0.08);
  --border-hover: rgba(0, 0, 0, 0.15);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;

  --accent: #0284c7;
  --accent-hover: #0369a1;
  --accent-glow: rgba(2, 132, 199, 0.1);
  --accent-secondary: #7c3aed;
  --accent-tertiary: #ea580c;

  --gradient-hero: linear-gradient(135deg, #f8fafc 0%, #e8e0f0 40%, #dbeafe 70%, #f8fafc 100%);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-hover);
}

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

/* ========================================
   Navigation
   ======================================== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: var(--bg-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  transition: all var(--transition-base);
}

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
}

.nav-logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: 0.5rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  transition: all var(--transition-fast);
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  width: 36px;
  height: 36px;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  border-color: var(--border-hover);
  color: var(--text-primary);
}

.admin-btn {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.8rem;
  padding: 0.4rem 0.75rem;
  border-radius: 8px;
  cursor: pointer;
  font-family: var(--font-body);
  transition: all var(--transition-fast);
}

.admin-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.admin-btn.authenticated {
  border-color: var(--accent-success);
  color: var(--accent-success);
}

/* Mobile nav */
.nav-hamburger {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

@media (max-width: 768px) {
  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition-base);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }

  .nav-hamburger {
    display: flex;
  }
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--gradient-hero);
  position: relative;
  overflow: hidden;
  padding: 2rem;
}

.hero::before {
  content: '';
  position: absolute;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  top: 20%;
  right: -10%;
  animation: float 20s ease-in-out infinite;
}

.hero::after {
  content: '';
  position: absolute;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(167, 139, 250, 0.08) 0%, transparent 70%);
  bottom: 10%;
  left: -5%;
  animation: float 15s ease-in-out infinite reverse;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0); }
  33% { transform: translate(30px, -30px); }
  66% { transform: translate(-20px, 20px); }
}

.hero-content {
  text-align: center;
  max-width: 720px;
  position: relative;
  z-index: 1;
}

.hero-avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  margin: 0 auto 2rem;
  border: 3px solid var(--border-color);
  background: var(--bg-card);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  color: var(--accent);
  overflow: hidden;
}

.hero-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 0.75rem;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-title-role {
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--accent);
  margin-bottom: 1.5rem;
  opacity: 0.8;
}

.hero p {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 540px;
  margin: 0 auto 2.5rem;
  line-height: 1.8;
}

.hero-social {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

.hero-social a {
  width: 44px;
  height: 44px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: 1.2rem;
  transition: all var(--transition-fast);
}

.hero-social a:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px var(--accent-glow);
}

.scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  color: var(--text-muted);
  font-size: 0.8rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* ========================================
   Sections - Common
   ======================================== */
.section {
  padding: var(--section-padding);
  max-width: 1200px;
  margin: 0 auto;
}

.section-header {
  text-align: center;
  margin-bottom: 4rem;
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 0.75rem;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
}

.section-subtitle {
  color: var(--text-secondary);
  font-size: 1.05rem;
  max-width: 520px;
  margin: 0 auto;
}

/* Fade-in animation */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ========================================
   Activity Calendar
   ======================================== */
.calendar-container {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--card-radius);
  padding: 2rem;
  overflow-x: auto;
}

.calendar-grid {
  display: grid;
  grid-template-columns: repeat(53, 1fr);
  gap: 3px;
  min-width: 700px;
}

.calendar-month-labels {
  display: grid;
  grid-template-columns: repeat(53, 1fr);
  gap: 3px;
  min-width: 700px;
  margin-bottom: 0.5rem;
}

.calendar-month-label {
  font-size: 0.7rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.calendar-cell {
  aspect-ratio: 1;
  border-radius: 3px;
  background: var(--bg-secondary);
  cursor: default;
  position: relative;
  transition: all var(--transition-fast);
}

.calendar-cell[data-count="1"] { background: rgba(56, 189, 248, 0.25); }
.calendar-cell[data-count="2"] { background: rgba(56, 189, 248, 0.45); }
.calendar-cell[data-count="3"] { background: rgba(56, 189, 248, 0.65); }
.calendar-cell[data-count="4"] { background: rgba(56, 189, 248, 0.85); }
.calendar-cell[data-count="5"] { background: var(--accent); }

.calendar-cell:hover {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.calendar-tooltip {
  position: fixed;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.5rem 0.75rem;
  border-radius: 8px;
  font-size: 0.8rem;
  pointer-events: none;
  z-index: 2000;
  max-width: 250px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.3);
  display: none;
}

.calendar-tooltip.visible {
  display: block;
}

.calendar-legend {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  justify-content: flex-end;
  margin-top: 1rem;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.calendar-legend-cell {
  width: 12px;
  height: 12px;
  border-radius: 2px;
}

/* ========================================
   Cards - Teachings, Research
   ======================================== */
.cards-filter {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
  margin-bottom: 2.5rem;
  flex-wrap: wrap;
}

.filter-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.4rem 1rem;
  border-radius: 20px;
  font-size: 0.825rem;
  font-family: var(--font-body);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--accent-glow);
  border-color: var(--accent);
  color: var(--accent);
}

.filter-description {
  max-width: 680px;
  margin: 0 auto 2rem;
  padding: 1rem 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
  display: none;
}

.filter-description.visible {
  display: block;
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--card-radius);
  padding: var(--card-padding);
  transition: all var(--transition-base);
  position: relative;
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15);
}

.card-type {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  padding: 0.25rem 0.6rem;
  border-radius: 6px;
  margin-bottom: 1rem;
}

.card-type.course {
  background: rgba(56, 189, 248, 0.15);
  color: var(--accent);
}

.card-type.workshop {
  background: rgba(167, 139, 250, 0.15);
  color: var(--accent-secondary);
}

.card-type.paper {
  background: rgba(52, 211, 153, 0.15);
  color: var(--accent-success);
}

.card-type.project {
  background: rgba(56, 189, 248, 0.15);
  color: var(--accent);
}

.card-type.notes,
.card-type.lectures {
  background: rgba(251, 191, 36, 0.15);
  color: #fbbf24;
}

.card h3 {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  letter-spacing: -0.01em;
}

.card-meta {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
  font-family: var(--font-mono);
}

.card p {
  font-size: 0.925rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 1rem;
}

.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.tag {
  font-size: 0.725rem;
  padding: 0.2rem 0.55rem;
  border-radius: 6px;
  background: var(--bg-secondary);
  color: var(--text-muted);
  border: 1px solid var(--border-color);
}

.card-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.85rem;
  font-weight: 500;
  margin-top: 0.5rem;
}

/* ========================================
   Blog / Rambling Thoughts
   ======================================== */
.blog-list {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.blog-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--card-radius);
  padding: var(--card-padding);
  cursor: pointer;
  transition: all var(--transition-base);
}

.blog-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-hover);
}

.blog-date {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.blog-card h3 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  letter-spacing: -0.01em;
}

.blog-excerpt {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* Blog post expanded view */
.blog-post-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(8px);
  z-index: 3000;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  overflow-y: auto;
  padding: 4rem 2rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
}

.blog-post-overlay.open {
  opacity: 1;
  pointer-events: all;
}

.blog-post-content {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--card-radius);
  padding: 3rem;
  max-width: 720px;
  width: 100%;
  position: relative;
  transform: translateY(20px);
  transition: transform var(--transition-base);
}

.blog-post-overlay.open .blog-post-content {
  transform: translateY(0);
}

.blog-post-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  width: 32px;
  height: 32px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.blog-post-close:hover {
  border-color: var(--accent-danger);
  color: var(--accent-danger);
}

.blog-post-content h1 {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
}

.blog-post-content .blog-date {
  margin-bottom: 2rem;
}

.blog-rendered h2 {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 600;
  margin: 2rem 0 1rem;
}

.blog-rendered h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 1.5rem 0 0.75rem;
}

.blog-rendered p {
  margin-bottom: 1rem;
  color: var(--text-secondary);
  line-height: 1.8;
}

.blog-rendered ul, .blog-rendered ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
  color: var(--text-secondary);
}

.blog-rendered li {
  margin-bottom: 0.4rem;
  line-height: 1.7;
}

.blog-rendered strong {
  color: var(--text-primary);
  font-weight: 600;
}

.blog-rendered code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--bg-secondary);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.blog-rendered pre {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.25rem;
  overflow-x: auto;
  margin-bottom: 1rem;
}

.blog-rendered pre code {
  background: none;
  padding: 0;
}

.blog-rendered blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 1rem;
  margin: 1rem 0;
  color: var(--text-muted);
  font-style: italic;
}

/* ========================================
   Notes Viewer
   ======================================== */
.notes-viewer {
  background: #fff;
  border-radius: var(--card-radius);
  max-width: 960px;
  width: 100%;
  height: 85vh;
  position: relative;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transform: translateY(20px);
  transition: transform var(--transition-base);
}

.blog-post-overlay.open .notes-viewer {
  transform: translateY(0);
}

.notes-viewer .blog-post-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  z-index: 10;
  background: rgba(0,0,0,0.06);
  border: none;
}

.notes-viewer iframe {
  width: 100%;
  flex: 1;
  border: none;
  border-radius: var(--card-radius);
}

/* ========================================
   Notes Pagination
   ======================================== */
.notes-pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-top: 2rem;
}

.notes-page-info {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ========================================
   Footer
   ======================================== */
.footer {
  border-top: 1px solid var(--border-color);
  padding: 3rem 2rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.footer a {
  color: var(--text-secondary);
}

/* ========================================
   Admin Elements
   ======================================== */
.admin-only {
  display: none !important;
}

body.admin-mode .admin-only {
  display: flex !important;
}

.add-btn {
  background: var(--bg-card);
  border: 2px dashed var(--border-color);
  border-radius: var(--card-radius);
  padding: 2rem;
  color: var(--text-muted);
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  width: 100%;
  font-family: var(--font-body);
  text-align: center;
}

.add-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-glow);
}

.card-admin-actions {
  position: absolute;
  top: 1rem;
  right: 1rem;
  display: flex;
  gap: 0.4rem;
}

.card-edit-btn,
.card-delete-btn {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  width: 28px;
  height: 28px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.card-edit-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.card-delete-btn:hover {
  border-color: var(--accent-danger);
  color: var(--accent-danger);
}

/* ========================================
   Modal
   ======================================== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(8px);
  z-index: 5000;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  overflow-y: auto;
  padding: 4rem 2rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
}

.modal-overlay.open {
  opacity: 1;
  pointer-events: all;
}

.modal {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--card-radius);
  padding: 2.5rem;
  max-width: 560px;
  width: 100%;
  position: relative;
}

.modal h2 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.65rem 0.85rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.9rem;
  transition: border-color var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--accent);
}

.form-group textarea {
  min-height: 120px;
  resize: vertical;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.6;
}

.form-actions {
  display: flex;
  gap: 0.75rem;
  justify-content: flex-end;
  margin-top: 1.5rem;
}

.btn {
  padding: 0.55rem 1.25rem;
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 500;
  font-family: var(--font-body);
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--accent);
  color: #000;
  border-color: var(--accent);
}

.btn-primary:hover {
  background: var(--accent-hover);
}

.btn-secondary {
  background: var(--bg-secondary);
  color: var(--text-secondary);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  border-color: var(--border-hover);
  color: var(--text-primary);
}

.btn-danger {
  background: rgba(248, 113, 113, 0.15);
  color: var(--accent-danger);
  border-color: rgba(248, 113, 113, 0.3);
}

.btn-danger:hover {
  background: rgba(248, 113, 113, 0.25);
}

/* ========================================
   Toast Notifications
   ======================================== */
.toast-container {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.toast {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 0.85rem 1.25rem;
  font-size: 0.875rem;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  animation: slideIn 0.3s ease;
  max-width: 360px;
}

.toast.success { border-color: var(--accent-success); }
.toast.error { border-color: var(--accent-danger); }
.toast.info { border-color: var(--accent); }

@keyframes slideIn {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

/* ========================================
   Loading Spinner
   ======================================== */
.spinner {
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-color);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  display: inline-block;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 768px) {
  :root {
    --section-padding: 4rem 1.25rem;
    --card-padding: 1.35rem;
  }

  .cards-grid {
    grid-template-columns: 1fr;
  }

  .hero h1 {
    font-size: 2.25rem;
  }

  .blog-post-content {
    padding: 2rem;
  }

  .modal {
    padding: 1.75rem;
  }
}