/* ========================================
   ToolHub — Flat Design System
   风格: Flat Design / 字体驱动 / 简洁线条
   字体: Rubik (标题) + Nunito Sans (正文)
   间距: 4/8dp 节奏系统
   动效: 150-200ms 全局过渡
   ======================================== */

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

/* --- Design Tokens: Light --- */
:root {
  --color-primary: #2563EB;
  --color-primary-hover: #1D4ED8;
  --color-primary-light: #EEF2FF;
  --color-secondary: #6366F1;
  --color-accent: #059669;
  --color-accent-hover: #047857;

  --color-bg: #FFFFFF;
  --color-bg-alt: #F8FAFC;
  --color-surface: #FFFFFF;
  --color-surface-hover: #F1F5F9;

  --color-text: #0F172A;
  --color-text-secondary: #475569;
  --color-text-muted: #94A3B8;

  --color-border: #E2E8F0;
  --color-border-light: #F1F5F9;

  --color-success: #059669;
  --color-warning: #D97706;
  --color-error: #DC2626;
  --color-destructive: #DC2626;

  --color-ring: #2563EB;

  /* Spacing scale (4dp base) */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;

  /* Typography */
  --font-heading: 'Rubik', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: 'Nunito Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Fira Mono', 'Roboto Mono', Menlo, monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.8125rem;
  --text-base: 0.9375rem;
  --text-lg: 1.0625rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 2rem;
  --text-4xl: 2.5rem;

  --leading-tight: 1.25;
  --leading-normal: 1.6;
  --leading-relaxed: 1.75;

  /* Radii */
  --radius-sm: 6px;
  --radius: 8px;
  --radius-md: 10px;
  --radius-lg: 12px;
  --radius-xl: 16px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition: 200ms ease;

  /* Layout */
  --max-width: 1152px;
}

/* --- Design Tokens: Dark --- */
[data-theme="dark"] {
  --color-bg: #0B1120;
  --color-bg-alt: #111827;
  --color-surface: #1A2332;
  --color-surface-hover: #202B3D;

  --color-text: #E2E8F0;
  --color-text-secondary: #94A3B8;
  --color-text-muted: #64748B;

  --color-border: #263348;
  --color-border-light: #1A2535;

  --color-primary: #3B82F6;
  --color-primary-hover: #60A5FA;
  --color-primary-light: rgba(59,130,246,0.12);

  --color-accent: #10B981;
  --color-accent-hover: #34D399;

  --color-ring: #3B82F6;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-bg: #0B1120;
    --color-bg-alt: #111827;
    --color-surface: #1A2332;
    --color-surface-hover: #202B3D;

    --color-text: #E2E8F0;
    --color-text-secondary: #94A3B8;
    --color-text-muted: #64748B;

    --color-border: #263348;
    --color-border-light: #1A2535;

    --color-primary: #3B82F6;
    --color-primary-hover: #60A5FA;
    --color-primary-light: rgba(59,130,246,0.12);

    --color-accent: #10B981;
    --color-accent-hover: #34D399;

    --color-ring: #3B82F6;
  }
}

/* --- Base --- */
html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: var(--leading-normal);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background var(--transition), color var(--transition);
}

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

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

::selection { background: var(--color-primary); color: #fff; }

/* --- Skip Link (a11y) --- */
.skip-link {
  position: absolute; top: -100%; left: var(--space-4);
  background: var(--color-primary); color: #fff;
  padding: var(--space-2) var(--space-4); border-radius: var(--radius-sm);
  z-index: 1000; font-weight: 600; font-size: var(--text-sm);
}
.skip-link:focus { top: var(--space-2); }

/* --- Utility --- */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--space-8); }

/* --- Navigation --- */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition), border-color var(--transition);
}

.nav-inner {
  max-width: var(--max-width); margin: 0 auto;
  padding: 0 var(--space-8); height: 60px;
  display: flex; align-items: center; justify-content: space-between;
}

.logo {
  font-family: var(--font-heading);
  font-size: var(--text-xl); font-weight: 700;
  color: var(--color-text); letter-spacing: -0.03em;
  display: flex; align-items: center; gap: var(--space-2);
  transition: opacity var(--transition-fast);
}
.logo:hover { color: var(--color-text); opacity: 0.75; }

.logo-svg { width: 28px; height: 28px; flex-shrink: 0; }

.nav-links { display: flex; align-items: center; gap: var(--space-1); }

.nav-links a {
  display: inline-flex; align-items: center;
  padding: 0.45rem 0.875rem; border-radius: var(--radius-sm);
  font-size: var(--text-sm); font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast), background var(--transition-fast);
}
.nav-links a:hover { color: var(--color-text); background: var(--color-surface-hover); }

.nav-links .nav-btn {
  background: var(--color-text); color: var(--color-bg);
  padding: 0.45rem 1.1rem; font-weight: 600;
}
.nav-links .nav-btn:hover { background: var(--color-text-secondary); color: var(--color-bg); }

/* Theme toggle */
.theme-toggle {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: var(--radius);
  border: 1px solid var(--color-border); background: transparent;
  cursor: pointer; color: var(--color-text-secondary);
  transition: all var(--transition-fast); margin-left: var(--space-1);
}
.theme-toggle:hover { color: var(--color-text); border-color: var(--color-text-muted); }
.theme-toggle svg { width: 18px; height: 18px; }
.theme-toggle .icon-moon { display: none; }
.theme-toggle .icon-sun { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: block; }
[data-theme="dark"] .theme-toggle .icon-sun { display: none; }

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .icon-moon { display: block; }
  :root:not([data-theme="light"]) .theme-toggle .icon-sun { display: none; }
}

/* Hamburger */
.hamburger {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: none; cursor: pointer;
  padding: var(--space-2); z-index: 101; border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}
.hamburger:hover { background: var(--color-surface-hover); }
.hamburger span {
  display: block; width: 22px; height: 2px;
  background: var(--color-text); border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition-fast);
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* --- Footer --- */
.footer {
  border-top: 1px solid var(--color-border-light);
  padding: var(--space-12) var(--space-8); text-align: center; margin-top: auto;
  transition: border-color var(--transition);
}
.footer p { color: var(--color-text-muted); font-size: var(--text-xs); }
.footer-links {
  margin-top: var(--space-3); display: flex; justify-content: center;
  gap: var(--space-6); flex-wrap: wrap;
}
.footer-links a { font-size: var(--text-xs); color: var(--color-text-secondary); }
.footer-links a:hover { color: var(--color-text); }

/* --- Hero --- */
.hero {
  padding: var(--space-20) var(--space-8); text-align: center;
  border-bottom: 1px solid var(--color-border-light);
  transition: border-color var(--transition);
}
.hero h1 {
  font-family: var(--font-heading);
  font-size: var(--text-4xl); font-weight: 700;
  letter-spacing: -0.04em; margin-bottom: var(--space-3);
  color: var(--color-text); line-height: var(--leading-tight);
}
.hero p {
  font-size: var(--text-lg); color: var(--color-text-secondary);
  max-width: 560px; margin: 0 auto var(--space-6);
  line-height: var(--leading-normal);
}
.hero-actions { display: flex; justify-content: center; gap: var(--space-3); flex-wrap: wrap; }

/* --- Buttons --- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: var(--space-2);
  padding: 0.6rem 1.5rem; font-size: var(--text-sm); font-weight: 600;
  border-radius: var(--radius); border: none; cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap; letter-spacing: 0.01em;
  font-family: var(--font-body); position: relative; overflow: hidden;
}
.btn:active { transform: scale(0.97); }

.btn-primary { background: var(--color-primary); color: #fff; }
.btn-primary:hover { background: var(--color-primary-hover); color: #fff; }

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

.btn-white { background: var(--color-bg); color: var(--color-text); border: 1px solid var(--color-border); }
.btn-white:hover { background: var(--color-surface-hover); }

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

.btn-ghost { background: transparent; color: var(--color-primary); }
.btn-ghost:hover { background: var(--color-primary-light); }

.btn-gray { background: #64748B; color: #fff; }
.btn-gray:hover { background: #475569; color: #fff; }

.btn-green { background: var(--color-success); color: #fff; }
.btn-green:hover { background: var(--color-accent-hover); color: #fff; }

.btn-sm { padding: 0.4rem 0.875rem; font-size: var(--text-xs); }
.btn-lg { padding: 0.75rem 2rem; font-size: var(--text-base); }

.btn:focus-visible {
  outline: 2px solid var(--color-ring); outline-offset: 2px;
}

/* --- Cards --- */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-6);
  transition: border-color var(--transition-fast), background var(--transition-fast);
  display: block; color: var(--color-text);
}
.card:hover {
  border-color: var(--color-primary);
  color: var(--color-text);
}

/* Tool card */
.tool-card {
  display: flex; align-items: flex-start; gap: var(--space-4);
}
.tool-card-icon {
  width: 44px; height: 44px; border-radius: var(--radius-md);
  background: var(--color-primary-light); color: var(--color-primary);
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.tool-card-icon svg { width: 22px; height: 22px; }
.tool-card-info { min-width: 0; }
.tool-card-info h3 {
  font-family: var(--font-heading);
  font-size: var(--text-base); font-weight: 600;
  margin-bottom: 2px; color: var(--color-text);
}
.tool-card-info p {
  font-size: var(--text-sm); color: var(--color-text-secondary);
  line-height: var(--leading-normal);
  overflow: hidden; display: -webkit-box;
  -webkit-line-clamp: 2; -webkit-box-orient: vertical;
}

/* AI tool card */
.ai-card-logo {
  width: 44px; height: 44px; border-radius: var(--radius-md);
  background: var(--color-bg-alt); color: var(--color-primary);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-heading); font-size: var(--text-lg); font-weight: 700;
  flex-shrink: 0; overflow: hidden;
}
.ai-card-logo img { width: 32px; height: 32px; object-fit: contain; }

/* --- Grid --- */
.grid { display: grid; gap: var(--space-4); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* --- Tool Page Layout --- */
.tool-page { padding: var(--space-12) var(--space-8); }
.tool-page-header { margin-bottom: var(--space-8); }
.tool-page-header h1 {
  font-family: var(--font-heading);
  font-size: var(--text-2xl); font-weight: 700;
  margin-bottom: var(--space-1); letter-spacing: -0.02em;
}
.tool-page-header p { color: var(--color-text-secondary); font-size: var(--text-sm); }

.tool-panels { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-4); }
.panel { display: flex; flex-direction: column; }
.panel-label {
  font-size: var(--text-xs); font-weight: 600;
  color: var(--color-text-secondary); margin-bottom: var(--space-2);
  text-transform: uppercase; letter-spacing: 0.05em;
}
.panel textarea,
.panel input[type="text"],
.panel input[type="number"] {
  width: 100%; border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 0.75rem;
  font-family: var(--font-mono); font-size: var(--text-sm);
  resize: vertical; outline: none;
  transition: border-color var(--transition-fast);
  background: var(--color-bg); color: var(--color-text);
  line-height: 1.7;
}
.panel textarea:focus,
.panel input:focus {
  border-color: var(--color-primary);
  outline: 2px solid var(--color-primary-light); outline-offset: -2px;
}
.panel textarea[readonly] { background: var(--color-bg-alt); }
.panel textarea { min-height: 360px; }

.tool-actions { display: flex; flex-wrap: wrap; gap: var(--space-2); margin-bottom: var(--space-5); }
.tool-status { font-size: var(--text-sm); align-self: center; margin-left: auto; font-weight: 500; }

/* Single panel form */
.tool-form {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-xl); padding: var(--space-8);
  max-width: 680px;
}
.tool-form .form-group { margin-bottom: var(--space-5); }
.tool-form .form-group label {
  display: block; font-size: var(--text-xs); font-weight: 600;
  color: var(--color-text-secondary); margin-bottom: var(--space-2);
}
.tool-form .form-row { display: flex; gap: var(--space-2); }
.tool-form input[type="text"],
.tool-form input[type="number"],
.tool-form input[type="file"] {
  flex: 1; border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 0.6rem 0.75rem;
  font-family: var(--font-mono); font-size: var(--text-sm);
  outline: none; background: var(--color-bg); color: var(--color-text);
  transition: border-color var(--transition-fast);
}
.tool-form input:focus {
  border-color: var(--color-primary);
  outline: 2px solid var(--color-primary-light); outline-offset: -2px;
}
.tool-result {
  font-family: var(--font-mono); font-size: var(--text-sm);
  line-height: 2; padding: var(--space-2) 0;
}
.tool-result .label-col { color: var(--color-text-secondary); display: inline-block; width: 88px; }

/* Tool form: standalone textarea & inputs */
.tool-textarea {
  width: 100%; border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 0.75rem;
  font-family: var(--font-mono); font-size: var(--text-sm);
  outline: none; resize: vertical; background: var(--color-bg);
  color: var(--color-text); line-height: 1.7;
  transition: border-color var(--transition-fast);
}
.tool-textarea:focus {
  border-color: var(--color-primary);
  outline: 2px solid var(--color-primary-light); outline-offset: -2px;
}
.tool-input-readonly {
  width: 100%; border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 0.6rem 0.75rem;
  font-family: var(--font-mono); font-size: var(--text-xs);
  outline: none; background: var(--color-bg-alt); color: var(--color-text);
}
.tool-input {
  width: 100%; border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 0.6rem 0.75rem;
  font-family: var(--font-mono); font-size: var(--text-sm);
  outline: none; background: var(--color-bg); color: var(--color-text);
  transition: border-color var(--transition-fast);
}
.tool-input:focus {
  border-color: var(--color-primary);
  outline: 2px solid var(--color-primary-light); outline-offset: -2px;
}

/* Hash result grid */
.hash-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-4); margin-top: var(--space-4); }

/* Stat card left-aligned */
.stat-card-left { text-align: left; }
.stat-card-left .stat-label { margin-top: 0; }
.stat-card-left .stat-value { font-size: 1rem; word-break: break-all; }

/* --- Category filter pills --- */
.filter-bar { display: flex; flex-wrap: wrap; gap: var(--space-2); margin-bottom: var(--space-8); }
.filter-pill {
  display: inline-flex; padding: 0.45rem 1rem; border-radius: 999px;
  font-size: var(--text-sm); font-weight: 500;
  background: var(--color-bg-alt); color: var(--color-text-secondary);
  transition: all var(--transition-fast); border: 1px solid transparent;
}
.filter-pill:hover { background: var(--color-surface-hover); color: var(--color-text); }
.filter-pill.active { background: var(--color-text); color: var(--color-bg); border-color: var(--color-text); }
.filter-pill.active:hover { background: var(--color-text-secondary); color: var(--color-bg); }

/* --- Tags & Badges --- */
.tag {
  display: inline-flex; padding: 0.18rem 0.6rem; border-radius: 999px;
  font-size: 0.6875rem; font-weight: 600; letter-spacing: 0.02em;
}
.tag-green { background: #ECFDF5; color: #059669; }
.tag-blue { background: #EEF2FF; color: #2563EB; }
.tag-purple { background: #F5F3FF; color: #7C3AED; }
.tag-yellow { background: #FFFBEB; color: #D97706; }
.tag-red { background: #FEF2F2; color: #DC2626; }

[data-theme="dark"] .tag-green { background: rgba(5,150,105,0.15); color: #34D399; }
[data-theme="dark"] .tag-blue { background: rgba(37,99,235,0.15); color: #60A5FA; }
[data-theme="dark"] .tag-purple { background: rgba(124,58,237,0.15); color: #A78BFA; }
[data-theme="dark"] .tag-yellow { background: rgba(217,119,6,0.15); color: #FBBF24; }
[data-theme="dark"] .tag-red { background: rgba(220,38,38,0.15); color: #F87171; }

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .tag-green { background: rgba(5,150,105,0.15); color: #34D399; }
  :root:not([data-theme="light"]) .tag-blue { background: rgba(37,99,235,0.15); color: #60A5FA; }
  :root:not([data-theme="light"]) .tag-purple { background: rgba(124,58,237,0.15); color: #A78BFA; }
  :root:not([data-theme="light"]) .tag-yellow { background: rgba(217,119,6,0.15); color: #FBBF24; }
  :root:not([data-theme="light"]) .tag-red { background: rgba(220,38,38,0.15); color: #F87171; }
}

/* Star icon for featured */
.featured-star { color: #F59E0B; font-size: 0.6875rem; margin-left: 2px; }

/* --- Ad slot --- */
/* --- Auth pages --- */
.auth-page {
  display: flex; align-items: center; justify-content: center;
  min-height: calc(100vh - 60px - 120px); padding: var(--space-12) var(--space-8);
}
.auth-card {
  width: 100%; max-width: 400px;
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-xl); padding: var(--space-10);
}
.auth-card h1 {
  font-family: var(--font-heading); font-size: var(--text-2xl);
  font-weight: 700; margin-bottom: var(--space-8); letter-spacing: -0.02em;
}
.auth-card .form-group { margin-bottom: var(--space-5); }
.auth-card label {
  display: block; font-size: var(--text-xs); font-weight: 600;
  margin-bottom: var(--space-2); color: var(--color-text-secondary);
}
.auth-card input[type="email"],
.auth-card input[type="password"],
.auth-card input[type="text"] {
  width: 100%; border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 0.7rem 0.75rem;
  font-size: var(--text-base); outline: none; font-family: var(--font-body);
  color: var(--color-text); background: var(--color-bg);
  transition: border-color var(--transition-fast);
}
.auth-card input:focus {
  border-color: var(--color-primary);
  outline: 2px solid var(--color-primary-light); outline-offset: -2px;
}
.auth-card button[type="submit"] {
  width: 100%; padding: 0.75rem; font-size: var(--text-base); font-weight: 600;
  background: var(--color-text); color: var(--color-bg);
  border: none; border-radius: var(--radius); cursor: pointer;
  transition: all var(--transition-fast); font-family: var(--font-body);
}
.auth-card button[type="submit"]:hover { background: var(--color-text-secondary); }
.auth-card button[type="submit"]:active { transform: scale(0.98); }
.auth-alt {
  text-align: center; font-size: var(--text-sm);
  color: var(--color-text-secondary); margin-top: var(--space-6);
}

.alert-error {
  background: #FEF2F2; border: 1px solid #FECACA; color: #DC2626;
  padding: 0.7rem 0.85rem; border-radius: var(--radius);
  font-size: var(--text-sm); margin-bottom: var(--space-5);
}
[data-theme="dark"] .alert-error { background: rgba(220,38,38,0.1); border-color: rgba(220,38,38,0.3); }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .alert-error { background: rgba(220,38,38,0.1); border-color: rgba(220,38,38,0.3); }
}

/* --- Dashboard --- */
.dashboard { padding: var(--space-12) var(--space-8); }
.dashboard-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: var(--space-10); flex-wrap: wrap; gap: var(--space-3);
}
.dashboard-header h1 {
  font-family: var(--font-heading); font-size: var(--text-2xl);
  font-weight: 700; letter-spacing: -0.02em;
}
.stat-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-4); margin-bottom: var(--space-10); }
.stat-card {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-6); text-align: center;
  transition: border-color var(--transition-fast);
}
.stat-card:hover { border-color: var(--color-primary); }
.stat-value { font-family: var(--font-heading); font-size: var(--text-3xl); font-weight: 700; letter-spacing: -0.02em; }
.stat-value.blue { color: var(--color-primary); }
.stat-value.green { color: var(--color-accent); }
.stat-label { font-size: var(--text-sm); color: var(--color-text-secondary); margin-top: var(--space-2); }

/* --- Section headings --- */
.section-title {
  font-family: var(--font-heading); font-size: var(--text-xl);
  font-weight: 700; margin-bottom: var(--space-4);
  display: flex; align-items: center; gap: var(--space-3);
  letter-spacing: -0.02em;
}
.section-title svg { width: 24px; height: 24px; color: var(--color-primary); flex-shrink: 0; }

/* --- Page header --- */
.page-header { margin-bottom: var(--space-8); }
.page-header h1 {
  font-family: var(--font-heading); font-size: var(--text-2xl);
  font-weight: 700; margin-bottom: var(--space-1); letter-spacing: -0.02em;
}
.page-header p { color: var(--color-text-secondary); font-size: var(--text-sm); }

/* --- Empty state --- */
.empty-state { text-align: center; padding: var(--space-20) var(--space-8); color: var(--color-text-muted); }
.empty-state svg { width: 48px; height: 48px; margin-bottom: var(--space-4); opacity: 0.4; }
.empty-state p:first-of-type { font-size: var(--text-lg); margin-bottom: var(--space-2); color: var(--color-text-secondary); }

/* --- Upgrade banner --- */
.upgrade-banner {
  background: var(--color-bg-alt); border: 1px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-6);
  transition: border-color var(--transition), background var(--transition);
}
.upgrade-banner h3 { font-family: var(--font-heading); font-weight: 600; margin-bottom: var(--space-1); font-size: var(--text-base); }
.upgrade-banner p { font-size: var(--text-sm); color: var(--color-text-secondary); margin-bottom: var(--space-3); }

/* --- Custom scrollbar --- */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--color-text-muted); }

/* --- Focus styles (a11y) --- */
:focus-visible { outline: 2px solid var(--color-ring); outline-offset: 2px; border-radius: 2px; }

/* --- Reduced motion --- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
}

/* ========================================
   Responsive
   ======================================== */

@media (max-width: 768px) {
  .container { padding: 0 var(--space-5); }
  .nav-inner { padding: 0 var(--space-5); }

  .hamburger { display: flex; }

  .nav-links {
    display: none; position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: var(--color-bg); flex-direction: column;
    align-items: center; justify-content: center;
    gap: var(--space-3); z-index: 100;
  }
  .nav-links.open { display: flex; }
  .nav-links a { font-size: var(--text-lg); padding: var(--space-3) var(--space-6); }

  .hero { padding: var(--space-12) var(--space-5); }
  .hero h1 { font-size: var(--text-3xl); }
  .hero p { font-size: var(--text-base); }

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

  .tool-panels { grid-template-columns: 1fr; }
  .tool-form { max-width: 100%; }
  .tool-page { padding: var(--space-8) var(--space-5); }

  .auth-card { max-width: 100%; }
}

@media (max-width: 480px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .stat-grid { grid-template-columns: 1fr; }

  .hero { padding: var(--space-10) var(--space-4); }
  .hero h1 { font-size: var(--text-2xl); }

  .tool-actions { flex-direction: column; }
  .tool-actions .btn { width: 100%; }
  .tool-status { margin-left: 0; }

  .tool-form .form-row { flex-direction: column; }
  .tool-page { padding: var(--space-6) var(--space-4); }

  .dashboard-header { flex-direction: column; align-items: flex-start; }
  .container { padding: 0 var(--space-4); }
  .nav-inner { padding: 0 var(--space-4); }
}