/* ==========================================================================
   AI To-Do List & Productivity Suite - Production Design System
   Modern, Fast, Accessible (WCAG AAA), 0-CLS Layout
   ========================================================================== */

:root {
  /* Color Palette - Modern High-Contrast Neutral & Indigo Accent */
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --bg-elevated: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-inverse: #ffffff;

  --accent-primary: #4f46e5;
  --accent-primary-hover: #4338ca;
  --accent-primary-light: #e0e7ff;
  --accent-text: #3730a3;

  --success: #10b981;
  --success-light: #ecfdf5;
  --success-text: #065f46;

  --warning: #f59e0b;
  --warning-light: #fffbeb;
  --warning-text: #92400e;

  --danger: #ef4444;
  --danger-light: #fef2f2;
  --danger-text: #991b1b;

  --info: #0ea5e9;
  --info-light: #f0f9ff;
  --info-text: #075985;

  --quad-q1: #ef4444;
  --quad-q1-bg: #fef2f2;
  --quad-q2: #3b82f6;
  --quad-q2-bg: #eff6ff;
  --quad-q3: #f59e0b;
  --quad-q3-bg: #fffbeb;
  --quad-q4: #6b7280;
  --quad-q4-bg: #f3f4f6;

  --border-color: #e2e8f0;
  --border-focus: #4f46e5;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.05);

  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  --max-w-content: 1200px;
  --max-w-article: 820px;
  --header-height: 70px;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-primary: #090d16;
  --bg-secondary: #111827;
  --bg-tertiary: #1f2937;
  --bg-elevated: #1e293b;
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-inverse: #0f172a;

  --accent-primary: #6366f1;
  --accent-primary-hover: #4f46e5;
  --accent-primary-light: rgba(99, 102, 241, 0.15);
  --accent-text: #c7d2fe;

  --success: #34d399;
  --success-light: rgba(16, 185, 129, 0.15);
  --success-text: #a7f3d0;

  --warning: #fbbf24;
  --warning-light: rgba(245, 158, 11, 0.15);
  --warning-text: #fde68a;

  --danger: #f87171;
  --danger-light: rgba(239, 68, 68, 0.15);
  --danger-text: #fecaca;

  --info: #38bdf8;
  --info-light: rgba(14, 165, 233, 0.15);
  --info-text: #bae6fd;

  --quad-q1: #f87171;
  --quad-q1-bg: rgba(239, 68, 68, 0.12);
  --quad-q2: #60a5fa;
  --quad-q2-bg: rgba(59, 130, 246, 0.12);
  --quad-q3: #fbbf24;
  --quad-q3-bg: rgba(245, 158, 11, 0.12);
  --quad-q4: #9ca3af;
  --quad-q4-bg: rgba(156, 163, 175, 0.12);

  --border-color: #334155;
  --border-focus: #818cf8;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6);
}

/* ==========================================================================
   Base & Reset
   ========================================================================== */

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

html {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  overflow-x: hidden;
}

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

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

a:hover {
  text-decoration: underline;
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  border: none;
  background: none;
}

ul, ol {
  padding-left: 1.5rem;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.25;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2rem, 4vw + 1rem, 2.75rem); margin-bottom: 0.75rem; }
h2 { font-size: clamp(1.5rem, 2.5vw + 0.5rem, 2rem); margin-top: 2rem; margin-bottom: 1rem; }
h3 { font-size: clamp(1.2rem, 1.5vw + 0.5rem, 1.45rem); margin-top: 1.5rem; margin-bottom: 0.75rem; }
p { margin-bottom: 1rem; color: var(--text-secondary); }

/* ==========================================================================
   Layout Containers
   ========================================================================== */

.container {
  width: 100%;
  max-width: var(--max-w-content);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.25rem;
  padding-right: 1.25rem;
}

.content-article {
  max-width: var(--max-w-article);
  margin-left: auto;
  margin-right: auto;
}

/* ==========================================================================
   Site Header & Navigation
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(248, 250, 252, 0.92);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition);
}

[data-theme="dark"] .site-header {
  background-color: rgba(9, 13, 22, 0.92);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  gap: 1rem;
}

@media (max-width: 768px) {
  :root {
    --header-height: 62px;
  }
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text-primary);
  text-decoration: none !important;
  flex-shrink: 0;
}

.logo-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent-primary), #8b5cf6);
  color: #ffffff;
  border-radius: var(--radius-md);
  font-weight: 900;
  box-shadow: var(--shadow-sm);
  flex-shrink: 0;
}

.nav-right-group {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-left: auto;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.15rem;
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 0.5rem 0.25rem;
  text-decoration: none !important;
  position: relative;
  transition: var(--transition);
  white-space: nowrap;
}

.nav-link:hover, .nav-link.active {
  color: var(--accent-primary);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--accent-primary);
  border-radius: var(--radius-full);
}

.nav-cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 1rem;
  font-size: 0.875rem;
  font-weight: 700;
  color: #ffffff !important;
  background: linear-gradient(135deg, var(--accent-primary), #7c3aed);
  border-radius: var(--radius-full);
  text-decoration: none !important;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  white-space: nowrap;
  min-height: 38px;
}

.nav-cta-btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  filter: brightness(1.08);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.theme-toggle-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  transition: var(--transition);
  cursor: pointer;
  font-size: 1.1rem;
}

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

.menu-toggle-btn {
  display: none;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  font-size: 1.35rem;
  transition: var(--transition);
  user-select: none;
}

.menu-toggle-btn:hover {
  border-color: var(--border-focus);
}

/* Mobile Nav Drawer & Backdrop */
.nav-backdrop {
  position: fixed;
  inset: 0;
  top: var(--header-height);
  background-color: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 98;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s ease, visibility 0.25s ease;
}

.nav-backdrop.open {
  opacity: 1;
  visibility: visible;
}

@media (max-width: 992px) {
  .menu-toggle-btn {
    display: inline-flex;
  }

  .nav-right-group .nav-cta-btn {
    display: none;
  }

  .nav-links {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    align-items: stretch;
    padding: 1.25rem 1.25rem 1.75rem 1.25rem;
    gap: 0.35rem;
    box-shadow: var(--shadow-xl);
    display: flex;
    max-height: calc(100vh - var(--header-height));
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    z-index: 99;
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.2s ease;
  }

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

  .nav-link {
    display: flex;
    align-items: center;
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1.05rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    color: var(--text-primary);
    min-height: 48px;
  }

  .nav-link:hover, .nav-link.active {
    background-color: var(--accent-primary-light);
    color: var(--accent-text);
  }

  .nav-link.active::after {
    display: none;
  }

  .nav-drawer-cta-wrapper {
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--border-color);
  }

  .nav-drawer-cta-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.85rem 1.25rem;
    font-size: 1rem;
    font-weight: 700;
    color: #ffffff !important;
    background: linear-gradient(135deg, var(--accent-primary), #7c3aed);
    border-radius: var(--radius-md);
    text-decoration: none !important;
    min-height: 48px;
    box-shadow: var(--shadow-md);
  }
}

/* ==========================================================================
   Hero & Header Section
   ========================================================================== */

.hero-section {
  padding: 2.5rem 0 1.5rem 0;
  text-align: center;
}

@media (max-width: 640px) {
  .hero-section {
    padding: 1.75rem 0 1rem 0;
  }
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.85rem;
  background-color: var(--accent-primary-light);
  color: var(--accent-text);
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  margin-bottom: 1rem;
}

.hero-title {
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
  font-size: clamp(1.85rem, 4.5vw + 0.5rem, 2.75rem);
}

.hero-subtitle {
  max-width: 680px;
  margin-left: auto;
  margin-right: auto;
  font-size: clamp(0.975rem, 1.8vw, 1.125rem);
  color: var(--text-secondary);
  line-height: 1.6;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-top: 2rem;
  flex-wrap: wrap;
}

@media (max-width: 540px) {
  .hero-cta-group {
    flex-direction: column;
    width: 100%;
    gap: 0.75rem;
  }

  .hero-cta-primary, .hero-cta-secondary {
    width: 100%;
    justify-content: center;
  }
}

.hero-cta-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 1.85rem;
  font-size: 1.05rem;
  font-weight: 700;
  color: #ffffff !important;
  background: linear-gradient(135deg, var(--accent-primary), #7c3aed);
  border-radius: var(--radius-full);
  text-decoration: none !important;
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.35);
  transition: var(--transition);
  min-height: 48px;
}

.hero-cta-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45);
  filter: brightness(1.08);
}

.hero-cta-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 1.6rem;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary) !important;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  text-decoration: none !important;
  transition: var(--transition);
  min-height: 48px;
}

.hero-cta-secondary:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--border-focus);
  transform: translateY(-2px);
}

/* App Interface Showcase Mockup */
.hero-mockup-wrapper {
  max-width: 960px;
  margin: 3rem auto 1rem auto;
  position: relative;
}

@media (max-width: 640px) {
  .hero-mockup-wrapper {
    margin: 1.75rem auto 1rem auto;
  }
}

.hero-mockup-wrapper::before {
  content: '';
  position: absolute;
  top: 15%;
  left: 20%;
  right: 20%;
  bottom: 10%;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.15), transparent 70%);
  filter: blur(40px);
  z-index: 0;
  pointer-events: none;
}

.hero-mockup-window {
  position: relative;
  z-index: 1;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  overflow: hidden;
  text-align: left;
}

.mockup-window-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.25rem;
  background-color: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-color);
  gap: 0.5rem;
}

@media (max-width: 480px) {
  .mockup-window-header {
    padding: 0.6rem 0.85rem;
  }
}

.mockup-window-dots {
  display: flex;
  gap: 6px;
  flex-shrink: 0;
}

.mockup-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.mockup-dot.red { background-color: #ef4444; }
.mockup-dot.yellow { background-color: #f59e0b; }
.mockup-dot.green { background-color: #10b981; }

.mockup-window-title {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.4rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.mockup-window-badge {
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.2rem 0.6rem;
  background-color: var(--accent-primary-light);
  color: var(--accent-text);
  border-radius: var(--radius-full);
  flex-shrink: 0;
}

.mockup-window-body {
  padding: 1.5rem 1.75rem;
}

@media (max-width: 640px) {
  .mockup-window-body {
    padding: 1rem 0.85rem;
  }
}

.trust-badges-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.75rem;
  flex-wrap: wrap;
  margin-top: 2rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

@media (max-width: 480px) {
  .trust-badges-row {
    gap: 0.85rem;
    font-size: 0.8rem;
  }
}

.trust-badge-item {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-weight: 600;
}

/* Value Props Bento Grid */
.bento-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 3rem 0;
}

@media (max-width: 640px) {
  .bento-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
    margin: 2rem 0;
  }
}

.bento-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

@media (max-width: 480px) {
  .bento-card {
    padding: 1.35rem 1.15rem;
  }
}

.bento-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-focus);
  box-shadow: var(--shadow-md);
}

.bento-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background-color: var(--accent-primary-light);
  color: var(--accent-text);
  border-radius: var(--radius-md);
  font-size: 1.5rem;
  margin-bottom: 1.25rem;
}

.step-flow-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

@media (max-width: 640px) {
  .step-flow-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
}

.step-flow-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  position: relative;
  transition: var(--transition);
}

@media (max-width: 480px) {
  .step-flow-card {
    padding: 1.25rem;
  }
}

.step-flow-card:hover {
  transform: translateY(-2px);
  border-color: var(--border-focus);
}

.step-flow-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background-color: var(--accent-primary-light);
  color: var(--accent-text);
  font-weight: 800;
  border-radius: var(--radius-full);
  margin-bottom: 1rem;
  font-size: 0.95rem;
}

.cta-banner-card {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.12), rgba(139, 92, 246, 0.12));
  border: 1px solid var(--accent-primary);
  border-radius: var(--radius-lg);
  padding: 3.5rem 2rem;
  text-align: center;
  margin: 4rem 0;
}

@media (max-width: 640px) {
  .cta-banner-card {
    padding: 2.25rem 1.25rem;
    margin: 2.5rem 0;
  }
}

.landing-preview-card {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-top: 1.5rem;
}

/* ==========================================================================
   AI To-Do List Interactive Tool
   ========================================================================== */

.tool-wrapper {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 1.75rem;
  margin: 1.5rem auto 3.5rem auto;
}

@media (max-width: 640px) {
  .tool-wrapper {
    padding: 1rem 0.85rem;
    border-radius: var(--radius-md);
    margin: 1rem auto 2.5rem auto;
  }
}

.prompt-box-wrapper {
  position: relative;
  margin-bottom: 1.25rem;
}

.prompt-textarea {
  width: 100%;
  min-height: 90px;
  padding: 1rem 1.25rem;
  font-size: 1rem;
  line-height: 1.5;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  resize: vertical;
  transition: var(--transition);
  -webkit-appearance: none;
}

@media (max-width: 640px) {
  .prompt-textarea {
    font-size: 16px; /* Prevents auto-zoom on iOS */
    padding: 0.85rem;
    min-height: 80px;
  }
}

.prompt-textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
  background-color: var(--bg-secondary);
  box-shadow: 0 0 0 4px var(--accent-primary-light);
}

.prompt-options-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

@media (max-width: 768px) {
  .prompt-options-bar {
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
  }
}

.prompt-select-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: flex-end;
}

@media (max-width: 768px) {
  .prompt-select-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
    width: 100%;
  }

  .prompt-select-group > div {
    width: 100%;
  }

  .prompt-select-group #open-api-settings-btn {
    grid-column: span 2;
    width: 100%;
  }
}

@media (max-width: 420px) {
  .prompt-select-group {
    grid-template-columns: 1fr;
  }

  .prompt-select-group #open-api-settings-btn {
    grid-column: span 1;
  }
}

.select-control {
  padding: 0.6rem 0.85rem;
  font-size: 0.875rem;
  font-weight: 500;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  cursor: pointer;
  transition: var(--transition);
  width: 100%;
  min-height: 42px;
  -webkit-appearance: none;
  appearance: none;
  background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  background-size: 1em;
  padding-right: 2.2rem;
}

.select-control:focus {
  outline: none;
  border-color: var(--accent-primary);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background-color: var(--accent-primary);
  color: #ffffff !important;
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: var(--radius-md);
  box-shadow: 0 2px 4px rgba(79, 70, 229, 0.25);
  transition: var(--transition);
  min-height: 46px;
  cursor: pointer;
}

@media (max-width: 768px) {
  .btn-primary {
    width: 100%;
    min-height: 48px;
    font-size: 1rem;
  }
}

.btn-primary:hover {
  background-color: var(--accent-primary-hover);
  box-shadow: 0 4px 10px rgba(79, 70, 229, 0.35);
  transform: translateY(-1px);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.55rem 0.9rem;
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  font-weight: 500;
  font-size: 0.875rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  transition: var(--transition);
  min-height: 42px;
  cursor: pointer;
}

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

/* Preset Chips Container */
.preset-chips-container {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
  font-size: 0.85rem;
}

@media (max-width: 640px) {
  .preset-chips-container {
    flex-wrap: nowrap;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    padding-bottom: 0.5rem;
    margin-bottom: 1.25rem;
    gap: 0.4rem;
  }

  .preset-chips-container::-webkit-scrollbar {
    height: 4px;
  }

  .preset-chips-container::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
  }
}

.preset-label {
  color: var(--text-muted);
  font-weight: 600;
  flex-shrink: 0;
}

.preset-chip {
  padding: 0.35rem 0.75rem;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
  font-size: 0.825rem;
  transition: var(--transition);
  white-space: nowrap;
  flex-shrink: 0;
  cursor: pointer;
  min-height: 36px;
  display: inline-flex;
  align-items: center;
}

.preset-chip:hover, .preset-chip:active {
  background-color: var(--accent-primary-light);
  color: var(--accent-text);
  border-color: var(--accent-primary);
}

/* Tool Dashboard Bar */
.tool-dashboard-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.25rem;
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: 1.25rem;
}

@media (max-width: 768px) {
  .tool-dashboard-bar {
    padding: 0.85rem;
    gap: 0.85rem;
  }
}

.stats-group {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}

@media (max-width: 680px) {
  .stats-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
    width: 100%;
  }

  .stat-item {
    background-color: var(--bg-secondary);
    padding: 0.6rem 0.75rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
  }
}

.stat-item {
  display: flex;
  flex-direction: column;
}

.stat-val {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-weight: 600;
}

.tool-dashboard-actions {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

@media (max-width: 680px) {
  .tool-dashboard-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.4rem;
    width: 100%;
  }

  .tool-dashboard-actions .btn-secondary {
    width: 100%;
    min-height: 42px;
    font-size: 0.825rem;
    padding: 0.4rem 0.5rem;
    justify-content: center;
  }
}

/* Progress bar */
.progress-container {
  width: 100%;
  height: 8px;
  background-color: var(--border-color);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-top: 0.5rem;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-primary), var(--success));
  border-radius: var(--radius-full);
  width: 0%;
  transition: width 0.3s ease;
}

/* View Mode Switcher & Filter Tabs */
.tool-controls-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

@media (max-width: 868px) {
  .tool-controls-row {
    flex-direction: column;
    align-items: stretch;
    gap: 0.6rem;
  }
}

.view-tabs, .filter-tabs {
  display: inline-flex;
  background-color: var(--bg-tertiary);
  padding: 3px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

@media (max-width: 868px) {
  .view-tabs {
    width: 100%;
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

  .view-tabs .tab-btn {
    text-align: center;
    justify-content: center;
    min-height: 40px;
  }

  .filter-tabs {
    width: 100%;
    display: flex;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    padding: 4px;
    gap: 4px;
  }

  .filter-tabs::-webkit-scrollbar {
    height: 3px;
  }

  .filter-tabs .tab-btn {
    white-space: nowrap;
    flex-shrink: 0;
    min-height: 38px;
  }
}

.tab-btn {
  display: inline-flex;
  align-items: center;
  padding: 0.45rem 0.85rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  border-radius: calc(var(--radius-md) - 2px);
  transition: var(--transition);
  cursor: pointer;
  user-select: none;
}

.tab-btn.active {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  box-shadow: var(--shadow-sm);
}

.task-search-wrapper {
  flex: 1;
  max-width: 240px;
  min-width: 180px;
}

@media (max-width: 868px) {
  .task-search-wrapper {
    max-width: 100%;
    width: 100%;
  }
}

/* Task Item Card */
.task-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  min-height: 80px;
}

.task-card {
  display: flex;
  align-items: flex-start;
  gap: 0.85rem;
  padding: 1rem 1.15rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  position: relative;
}

@media (max-width: 560px) {
  .task-card {
    padding: 0.85rem 0.85rem 0.95rem 0.85rem;
    gap: 0.65rem;
  }
}

.task-card:hover {
  border-color: #cbd5e1;
  box-shadow: var(--shadow-md);
}

[data-theme="dark"] .task-card:hover {
  border-color: #475569;
}

.task-card.completed {
  opacity: 0.65;
  background-color: var(--bg-primary);
}

.task-checkbox-wrapper {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 36px;
  min-height: 36px;
  flex-shrink: 0;
  margin-top: -4px;
}

.task-checkbox {
  appearance: none;
  -webkit-appearance: none;
  width: 24px;
  height: 24px;
  border: 2px solid var(--border-color);
  border-radius: 6px;
  outline: none;
  cursor: pointer;
  display: grid;
  place-content: center;
  transition: var(--transition);
}

.task-checkbox:checked {
  background-color: var(--success);
  border-color: var(--success);
}

.task-checkbox:checked::before {
  content: "✓";
  color: white;
  font-size: 15px;
  font-weight: 800;
}

.task-body {
  flex: 1;
  min-width: 0;
}

.task-title {
  font-size: 0.975rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
  word-break: break-word;
  line-height: 1.4;
}

.task-card.completed .task-title {
  text-decoration: line-through;
  color: var(--text-muted);
}

.task-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
  line-height: 1.5;
  word-break: break-word;
}

.task-meta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.775rem;
  margin-top: 0.35rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.22rem 0.6rem;
  border-radius: var(--radius-full);
  font-weight: 600;
  white-space: nowrap;
  font-size: 0.75rem;
}

.badge-time {
  background-color: var(--bg-tertiary);
  color: var(--text-secondary);
}

.badge-q1 { background-color: var(--quad-q1-bg); color: var(--quad-q1); }
.badge-q2 { background-color: var(--quad-q2-bg); color: var(--quad-q2); }
.badge-q3 { background-color: var(--quad-q3-bg); color: var(--quad-q3); }
.badge-q4 { background-color: var(--quad-q4-bg); color: var(--quad-q4); }

.badge-priority-high { background-color: var(--danger-light); color: var(--danger-text); }
.badge-priority-med { background-color: var(--warning-light); color: var(--warning-text); }
.badge-priority-low { background-color: var(--info-light); color: var(--info-text); }

.task-actions {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  flex-shrink: 0;
}

.task-action-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  transition: var(--transition);
  font-size: 1.05rem;
  cursor: pointer;
}

.task-action-btn:hover, .task-action-btn:active {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.task-action-btn.delete:hover, .task-action-btn.delete:active {
  background-color: var(--danger-light);
  color: var(--danger);
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 2.5rem 1rem;
  color: var(--text-muted);
}

.empty-state-icon {
  font-size: 2.5rem;
  margin-bottom: 0.75rem;
}

/* Matrix Quadrant View */
.matrix-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-top: 1rem;
}

@media (max-width: 768px) {
  .matrix-grid {
    grid-template-columns: 1fr;
    gap: 0.85rem;
  }
}

.matrix-quadrant {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem;
  min-height: 180px;
}

@media (max-width: 480px) {
  .matrix-quadrant {
    padding: 0.85rem 0.65rem;
  }
}

.matrix-quadrant-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.85rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
}

.matrix-quadrant-title {
  font-size: 0.925rem;
  font-weight: 700;
}

/* Manual Task Add Bar */
.manual-add-box {
  display: flex;
  gap: 0.6rem;
  margin-top: 1.25rem;
  padding-top: 1.25rem;
  border-top: 1px dashed var(--border-color);
  flex-wrap: wrap;
}

@media (max-width: 580px) {
  .manual-add-box {
    flex-direction: column;
  }

  .manual-add-input, .manual-add-box select, .manual-add-box button {
    width: 100% !important;
  }
}

.manual-add-input {
  flex: 1;
  padding: 0.65rem 0.9rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-size: 16px; /* Prevents auto-zoom on iOS */
  min-height: 42px;
}

.manual-add-input:focus {
  outline: none;
  border-color: var(--accent-primary);
}

/* ==========================================================================
   Article & SEO Rich Content Sections
   ========================================================================== */

.seo-section {
  padding: 2.5rem 0;
  border-top: 1px solid var(--border-color);
}

.seo-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-sm);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin: 1.75rem 0;
}

.feature-card {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  margin-bottom: 1rem;
  background-color: var(--accent-primary-light);
  color: var(--accent-text);
}

/* Comparison Table */
.comparison-table-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: 2rem 0;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.95rem;
  min-width: 540px;
}

.comparison-table th, .comparison-table td {
  padding: 0.85rem 1rem;
  border: 1px solid var(--border-color);
}

@media (max-width: 640px) {
  .comparison-table th, .comparison-table td {
    padding: 0.65rem 0.75rem;
    font-size: 0.85rem;
  }
}

.comparison-table th {
  background-color: var(--bg-tertiary);
  font-weight: 700;
  color: var(--text-primary);
}

.comparison-table tr:nth-child(even) {
  background-color: var(--bg-primary);
}

/* FAQ Accordion */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1.5rem;
}

.faq-item {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.15rem 1.35rem;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  text-align: left;
  background-color: transparent;
  transition: var(--transition);
  cursor: pointer;
}

@media (max-width: 640px) {
  .faq-question {
    padding: 1rem;
    font-size: 0.975rem;
  }
}

.faq-question:hover {
  background-color: var(--bg-primary);
}

.faq-icon {
  font-size: 1.25rem;
  transition: transform 0.2s ease;
  color: var(--text-muted);
  flex-shrink: 0;
  margin-left: 0.5rem;
}

.faq-item.open .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 1.35rem 1.25rem 1.35rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.65;
  display: none;
}

@media (max-width: 640px) {
  .faq-answer {
    padding: 0 1rem 1rem 1rem;
    font-size: 0.875rem;
  }
}

.faq-item.open .faq-answer {
  display: block;
}

/* Tools Directory Grid */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

@media (max-width: 640px) {
  .tools-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
}

.tool-card {
  display: flex;
  flex-direction: column;
  padding: 1.5rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  text-decoration: none !important;
  color: inherit;
}

@media (max-width: 480px) {
  .tool-card {
    padding: 1.25rem;
  }
}

.tool-card:hover {
  border-color: var(--accent-primary);
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}

.tool-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.tool-card-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  flex: 1;
  margin-bottom: 1rem;
}

.tool-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-primary);
}

/* ==========================================================================
   Modals & Toast
   ========================================================================== */

.modal-backdrop {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 999;
  padding: 1rem;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.modal-backdrop.open {
  opacity: 1;
  visibility: visible;
}

.modal-card {
  width: 100%;
  max-width: 520px;
  max-height: 90vh;
  overflow-y: auto;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  padding: 1.75rem;
  transform: scale(0.95);
  transition: var(--transition);
}

@media (max-width: 640px) {
  .modal-card {
    padding: 1.25rem 1rem;
    border-radius: var(--radius-md);
  }
}

.modal-backdrop.open .modal-card {
  transform: scale(1);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.modal-title {
  font-size: 1.25rem;
  font-weight: 700;
}

.modal-close-btn {
  font-size: 1.5rem;
  color: var(--text-muted);
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.modal-close-btn:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.toast {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 1000;
  padding: 0.75rem 1.25rem;
  background-color: var(--text-primary);
  color: var(--bg-primary);
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transform: translateY(100px);
  opacity: 0;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  pointer-events: none;
  max-width: calc(100vw - 3rem);
}

@media (max-width: 520px) {
  .toast {
    bottom: 1rem;
    right: 1rem;
    left: 1rem;
    max-width: none;
    justify-content: center;
    text-align: center;
  }
}

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

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  margin-top: auto;
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 3.5rem 0 2rem 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 2.5rem;
  margin-bottom: 2.5rem;
}

@media (max-width: 868px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 520px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

.footer-brand p {
  font-size: 0.9rem;
  margin-top: 0.5rem;
  max-width: 320px;
}

.footer-col-title {
  font-size: 0.95rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.footer-links {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--accent-primary);
}

.footer-bottom {
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}