/* ① THEME VARIABLES */
:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-card: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --accent: #6366f1;
  --accent-hover: #4f46e5;
  --border: #e2e8f0;
  --card-shadow: 0 1px 3px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.04);
  --transition: all .25s ease;
  --bg-primary-rgb: 255, 255, 255;
}
[data-theme="dark"] {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: #1a1a26;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #475569;
  --accent: #818cf8;
  --accent-hover: #6366f1;
  --border: #1e293b;
  --card-shadow: 0 1px 3px rgba(0,0,0,.3), 0 4px 16px rgba(0,0,0,.2);
  --bg-primary-rgb: 10, 10, 15;
}

/* ② THEME TOGGLE */
.theme-switch-wrapper { display: flex; align-items: center; }
.theme-switch { position: relative; display: inline-block; width: 62px; height: 32px; }
.theme-switch input { opacity: 0; width: 0; height: 0; }
.slider {
  position: absolute; cursor: pointer; inset: 0;
  background: #e2e8f0; border-radius: 34px;
  transition: all .4s ease;
  display: flex; align-items: center; padding: 0 3px;
  border: 2px solid transparent;
}
.slider.round { border-radius: 34px; }
input:checked + .slider { 
  background: #12121a; 
  border: 2px solid #2563eb; 
}
.thumb {
  width: 24px; height: 24px;
  background: white; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  transition: transform .45s cubic-bezier(0.68, -0.55, 0.265, 1.55), background .4s, box-shadow .4s;
  box-shadow: 0 2px 6px rgba(0,0,0,.15);
}
input:checked + .slider .thumb { 
  transform: translateX(30px); 
  background: #1e293b; 
  box-shadow: inset 0 0 0 1px #334155, 0 2px 6px rgba(0,0,0,.3);
}
.sun-icon, .moon-icon {
  width: 14px; height: 14px;
  position: absolute;
  transition: opacity .3s ease, transform .4s ease;
}
.sun-icon { opacity: 1; color: #f97316; transform: rotate(0); }
.moon-icon { opacity: 0; color: #60a5fa; transform: rotate(90deg); }
input:checked + .slider .sun-icon { opacity: 0; transform: rotate(-90deg); }
input:checked + .slider .moon-icon { opacity: 1; transform: rotate(0); }

/* ③ BENTO GRID */
.bento-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
}
.bento-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.5rem;
  box-shadow: var(--card-shadow);
  transition: var(--transition);
  text-decoration: none;
  display: block;
  color: var(--text-primary);
}
.bento-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(99,102,241,.12);
  border-color: var(--accent);
}
.bento-card.featured { grid-column: span 2; min-height: 180px; }

/* ④ SCROLL ANIMATIONS */
.fade-in-up {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .55s ease, transform .55s ease;
}
.fade-in-up.visible { opacity: 1; transform: translateY(0); }

/* ⑤ CALCULATOR SHARED STYLES */
.calc-input {
  width: 100%;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: .65rem 1rem;
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color .2s;
  outline: none;
}
.calc-input:focus { border-color: var(--accent); }
.calc-btn {
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 10px;
  padding: .75rem 2rem;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background .2s, transform .15s;
}
.calc-btn:hover { background: var(--accent-hover); transform: scale(1.02); }
.result-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
  margin-top: 1.25rem;
}
.gradient-text {
  background: linear-gradient(135deg, var(--accent), #a855f7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ⑥ NAVBAR STYLES */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background: rgba(var(--bg-primary-rgb), 0.45);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

@media (max-width: 768px) {
  .bento-grid {
    grid-template-columns: 1fr;
  }
  .bento-card.featured {
    grid-column: span 1;
  }
}


/* Print Styles for PDF Generation */
@media print {
  .navbar, footer, .ad-slot, .pdf-btn {
    display: none !important;
  }
  body {
    background: white !important;
    color: black !important;
  }
  .bento-card {
    box-shadow: none !important;
    border: 1px solid #ddd !important;
    break-inside: avoid;
  }
}