:root {
  /* Institutional Design Tokens - Academic & Government Database Style */
  --color-primary: #0b2e59;           /* Deep Parliamentary Navy */
  --color-primary-hover: #071e3d;
  --color-primary-subtle: #edf2f7;

  --color-bg: #f4f6f8;                /* Archival Paper Light Gray */
  --color-bg-card: #ffffff;
  --color-bg-hover: #f8fafc;
  --color-bg-subtle: #f1f4f8;

  --color-text: #1a202c;              /* High contrast crisp dark */
  --color-text-secondary: #4a5568;
  --color-text-muted: #718096;

  --color-border: #cbd5e1;            /* Crisp 1px rule */
  --color-border-subtle: #e2e8f0;
  --color-border-dark: #94a3b8;

  --color-error: #991b1b;
  --color-error-bg: #fef2f2;
  --color-error-border: #f87171;
  --color-success: #166534;
  --color-success-bg: #f0fdf4;
  --color-warning: #854d0e;
  --color-warning-bg: #fefce8;
  --color-warning-border: #fde047;
  --color-info: #1e3a8a;
  --color-info-bg: #eff6ff;
  --color-info-border: #93c5fd;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang TC", "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  --font-family-mono: ui-monospace, SFMono-Regular, "Liberation Mono", Menlo, Consolas, monospace;
  --font-family-serif: "Songti TC", "Noto Serif TC", SimSun, serif;

  --font-size-xs: 0.75rem;    /* 12px */
  --font-size-sm: 0.8125rem;  /* 13px */
  --font-size-base: 0.875rem; /* 14px - Higher information density */
  --font-size-md: 0.9375rem;  /* 15px */
  --font-size-lg: 1.0625rem;  /* 17px */
  --font-size-xl: 1.25rem;    /* 20px */
  --font-size-2xl: 1.5rem;    /* 24px */

  /* Spacing */
  --space-1: 3px;
  --space-2: 6px;
  --space-3: 10px;
  --space-4: 14px;
  --space-5: 18px;
  --space-6: 22px;
  --space-8: 28px;
  --space-10: 36px;

  /* Restrained Geometry - Minimal or Sharp Radii */
  --radius-sm: 2px;
  --radius-md: 2px;
  --radius-lg: 3px;
  --radius-full: 2px;

  /* Shadows - Minimal or Flat */
  --shadow-sm: none;
  --shadow-md: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 2px 4px rgba(0, 0, 0, 0.08);
  --shadow-hover: none;

  --transition: color 0.1s ease, background-color 0.1s ease, border-color 0.1s ease;
  --max-width: 1240px;
}

[data-theme="dark"] {
  --color-primary: #60a5fa;
  --color-primary-hover: #93c5fd;
  --color-primary-subtle: #1e293b;

  --color-bg: #0f172a;
  --color-bg-card: #182234;
  --color-bg-hover: #223049;
  --color-bg-subtle: #1e293b;

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

  --color-border: #334155;
  --color-border-subtle: #1e293b;
  --color-border-dark: #475569;

  --color-error: #f87171;
  --color-error-bg: #2d1215;
  --color-error-border: #7f1d1d;
  --color-success: #4ade80;
  --color-success-bg: #062b16;
  --color-warning: #facc15;
  --color-warning-bg: #2b2207;
  --color-warning-border: #713f12;
  --color-info: #60a5fa;
  --color-info-bg: #0f274a;
  --color-info-border: #1e40af;
}

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.5;
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

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

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

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

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

/* Header - Institutional Portal Style */
#app-header {
  background-color: #0b2e59;
  border-bottom: 2px solid #071e3d;
  color: #ffffff;
  position: sticky;
  top: 0;
  z-index: 100;
}

[data-theme="dark"] #app-header {
  background-color: #0d1b2a;
  border-bottom: 1px solid #1e293b;
}

.header-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-3) var(--space-4);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  color: #ffffff;
  text-decoration: none;
}

.brand:hover {
  text-decoration: none;
  opacity: 0.95;
}

.brand-badge {
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.3);
  color: #ffffff;
  font-size: var(--font-size-xs);
  padding: 2px 7px;
  font-family: var(--font-family-mono);
  letter-spacing: 0.05em;
  font-weight: 600;
  border-radius: var(--radius-sm);
}

.brand-title {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1.2;
}

.brand-subtitle {
  font-size: var(--font-size-xs);
  color: rgba(255, 255, 255, 0.75);
  letter-spacing: 0.01em;
  font-weight: 400;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.nav-link {
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.85);
  padding: 5px 10px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.nav-link:hover {
  color: #ffffff;
  text-decoration: none;
  background-color: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.2);
}

.nav-link.active {
  color: #ffffff;
  background-color: rgba(255, 255, 255, 0.18);
  border-color: rgba(255, 255, 255, 0.35);
  font-weight: 600;
}

.theme-toggle-btn {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: var(--radius-sm);
  padding: 4px 8px;
  font-size: var(--font-size-xs);
  color: #ffffff;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: var(--transition);
}

.theme-toggle-btn:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* Main Container */
#app-root {
  flex: 1;
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  padding: var(--space-5) var(--space-4) var(--space-8);
}

/* Footer - Official Document Notice Style */
#app-footer {
  background-color: var(--color-bg-card);
  border-top: 1px solid var(--color-border);
  padding: var(--space-5) var(--space-4);
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.footer-container {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-3);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--color-border-subtle);
}

.footer-links {
  display: flex;
  gap: var(--space-4);
}

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

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

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-3);
  color: var(--color-text-muted);
}

/* Toast Container */
#toast-container {
  position: fixed;
  bottom: var(--space-5);
  right: var(--space-5);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  pointer-events: none;
  max-width: 420px;
  width: calc(100vw - 32px);
}

.toast {
  pointer-events: auto;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  background-color: var(--color-bg-card);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  font-size: var(--font-size-sm);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.toast-error {
  border-left-color: var(--color-error);
  background-color: var(--color-error-bg);
  border-color: var(--color-error-border);
  color: var(--color-error);
}

.toast-success {
  border-left-color: var(--color-success);
  background-color: var(--color-success-bg);
  color: var(--color-success);
}