:root {
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #0f172a;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --radius: 12px;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(255, 255, 255, 0.5);
}

[data-theme="dark"] {
  --primary: #60a5fa;
  --primary-hover: #93c5fd;
  --bg: #0f172a;
  --surface: #1e293b;
  --text: #f8fafc;
  --text-muted: #94a3b8;
  --border: #334155;
  --glass-bg: rgba(30, 41, 59, 0.7);
  --glass-border: rgba(255, 255, 255, 0.1);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background-color 0.3s, color 0.3s;
  overflow-x: hidden;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.2s;
}

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

button {
  cursor: pointer;
  font-family: inherit;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: var(--glass-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.nav-links a {
  color: var(--text-muted);
  font-weight: 500;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  font-weight: 600;
  border: none;
  transition: all 0.2s;
  text-decoration: none;
  gap: 0.5rem;
}

.btn-primary {
  background-color: var(--primary);
  color: white !important;
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow);
}

.btn-outline {
  background-color: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}

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

/* Hero */
.hero {
  padding: 5rem 0;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: 1rem;
  line-height: 1.2;
}

.hero p {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto 2rem;
}

/* Cards */
.card {
  background-color: var(--surface);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

/* Grid */
.grid {
  display: grid;
  gap: 2rem;
}

.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 1024px) {
  .grid-cols-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-cols-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .nav-links { display: none; } /* Add mobile menu later */
  .grid-cols-2, .grid-cols-3, .grid-cols-4 { grid-template-columns: 1fr; }
  .hero h1 { font-size: 2.5rem; }
}

/* Generator Tool */
.generator-container {
  max-width: 800px;
  margin: 0 auto;
}

.password-display {
  display: flex;
  align-items: center;
  gap: 1rem;
  background-color: var(--bg);
  padding: 1rem 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin-bottom: 2rem;
  font-family: monospace;
  font-size: 1.5rem;
}

#passwordOutput {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--text);
  font-family: monospace;
  font-size: 1.5rem;
  outline: none;
}

.strength-meter {
  height: 8px;
  background-color: var(--border);
  border-radius: 4px;
  margin: 1rem 0 2rem;
  overflow: hidden;
}

.strength-meter-fill {
  height: 100%;
  width: 0%;
  transition: width 0.3s, background-color 0.3s;
}

.controls-group {
  margin-bottom: 1.5rem;
}

.controls-group label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 500;
  margin-bottom: 0.5rem;
}

.range-slider {
  width: 100%;
  accent-color: var(--primary);
}

.checkbox-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-weight: normal;
}

/* Footer */
footer {
  background-color: var(--surface);
  border-top: 1px solid var(--border);
  padding: 4rem 0 2rem;
  margin-top: 4rem;
}

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

.footer-grid h3 {
  margin-bottom: 1rem;
}

.footer-grid ul {
  list-style: none;
}

.footer-grid ul li {
  margin-bottom: 0.5rem;
}

@media (max-width: 768px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 480px) {
  .footer-grid { grid-template-columns: 1fr; }
}

/* Utility */
.text-center { text-align: center; }
.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-4 { margin-bottom: 1rem; }
.mb-8 { margin-bottom: 2rem; }
.mt-4 { margin-top: 1rem; }
.mt-8 { margin-top: 2rem; }

.section { padding: 4rem 0; }

.history-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem;
  border-bottom: 1px solid var(--border);
}
.text-sm { font-size: 0.875rem; }
.text-lg { font-size: 1.125rem; }
.font-medium { font-weight: 500; }

.breadcrumb a {
  color: var(--text-muted);
}
.breadcrumb a:hover {
  color: var(--primary);
}
.breadcrumb span {
  color: var(--text);
  font-weight: 500;
}

/* Reading Progress */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background-color: var(--primary);
  z-index: 1000;
  transition: width 0.1s;
}

/* Toasts */
.toast-container {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 9999;
  pointer-events: none;
}
.toast {
  background-color: var(--surface);
  color: var(--text);
  padding: 12px 24px;
  border-radius: 50px;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
  font-weight: 500;
  opacity: 0;
  transform: translateY(20px);
  animation: toast-in 0.3s forwards;
  pointer-events: all;
}
.toast.toast-fade-out {
  animation: toast-out 0.3s forwards;
}
@keyframes toast-in {
  to { opacity: 1; transform: translateY(0); }
}
@keyframes toast-out {
  to { opacity: 0; transform: translateY(-20px); }
}

/* Accessibility Focus */
:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

/* Skeleton Loading */
.skeleton {
  background: linear-gradient(90deg, var(--border) 25%, var(--bg) 50%, var(--border) 75%);
  background-size: 200% 100%;
  animation: loading 1.5s infinite;
  border-radius: var(--radius);
}
@keyframes loading {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

html {
  scroll-behavior: smooth;
}