/* SphereX v2 — Design System
 * Dark mode first, glass morphism, smooth animations.
 * Reference: docs/architecture/ui-design-system.md
 */

:root {
  /* Palette — Dark (default) */
  --bg: #0B0D12;
  --surface: #13161D;
  --surface-elevated: #1A1E27;
  --surface-glass: rgba(26, 30, 39, 0.65);
  --border: #272C38;
  --border-strong: #353B4A;
  --text: #F5F7FA;
  --text-secondary: #A0A8B7;
  --text-tertiary: #5E6678;
  --accent: #6366F1;
  --accent-hover: #7C7FF5;
  --accent-soft: rgba(99, 102, 241, 0.12);
  --success: #10B981;
  --success-soft: rgba(16, 185, 129, 0.12);
  --warning: #F59E0B;
  --warning-soft: rgba(245, 158, 11, 0.12);
  --danger: #EF4444;
  --danger-soft: rgba(239, 68, 68, 0.12);
  --info: #3B82F6;

  /* Spacing scale (4px step) */
  --sp-1: 4px;
  --sp-2: 8px;
  --sp-3: 12px;
  --sp-4: 16px;
  --sp-5: 20px;
  --sp-6: 24px;
  --sp-7: 32px;
  --sp-8: 40px;
  --sp-9: 48px;
  --sp-10: 64px;
  --sp-11: 80px;
  --sp-12: 96px;

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-pill: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.45);
  --shadow-glow: 0 0 0 3px rgba(99, 102, 241, 0.25);

  /* Easing */
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  --t-fast: 150ms;
  --t-default: 250ms;
  --t-slow: 400ms;

  /* Type */
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI Variable', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;
}

[data-theme='light'] {
  --bg: #FFFFFF;
  --surface: #F8F9FB;
  --surface-elevated: #FFFFFF;
  --surface-glass: rgba(255, 255, 255, 0.7);
  --border: #E5E7EB;
  --border-strong: #D1D5DB;
  --text: #0B0D12;
  --text-secondary: #4B5563;
  --text-tertiary: #9CA3AF;
}

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

html, body {
  height: 100%;
  font-family: var(--font);
  font-size: 14px;
  line-height: 1.5;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-image:
    radial-gradient(at 20% 0%, rgba(99, 102, 241, 0.08) 0px, transparent 50%),
    radial-gradient(at 80% 100%, rgba(99, 102, 241, 0.05) 0px, transparent 50%);
  background-attachment: fixed;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--t-fast) var(--ease);
}

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

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

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

::selection {
  background: var(--accent-soft);
  color: var(--text);
}

/* Typography */
h1 { font-size: 28px; font-weight: 700; line-height: 1.25; letter-spacing: -0.02em; }
h2 { font-size: 22px; font-weight: 600; line-height: 1.3; letter-spacing: -0.01em; }
h3 { font-size: 18px; font-weight: 600; line-height: 1.35; }
h4 { font-size: 16px; font-weight: 600; line-height: 1.4; }
.text-display { font-size: 36px; font-weight: 700; line-height: 1.2; letter-spacing: -0.02em; }
.text-sm { font-size: 12px; }
.text-secondary { color: var(--text-secondary); }
.text-tertiary { color: var(--text-tertiary); }
.text-mono { font-family: var(--font-mono); }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
  padding: 10px 16px;
  font-size: 14px;
  font-weight: 500;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--t-fast) var(--ease);
  white-space: nowrap;
  user-select: none;
}

.btn:focus-visible {
  outline: none;
  box-shadow: var(--shadow-glow);
}

.btn-primary {
  background: var(--accent);
  color: white;
}
.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}
.btn-primary:active {
  transform: translateY(0);
}

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

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}
.btn-ghost:hover {
  background: var(--surface);
  color: var(--text);
}

.btn-danger {
  background: var(--danger);
  color: white;
}
.btn-danger:hover {
  filter: brightness(1.1);
}

.btn-sm {
  padding: 6px 10px;
  font-size: 12px;
}

.btn-lg {
  padding: 14px 22px;
  font-size: 15px;
}

.btn[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

/* Inputs */
.field {
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
}

.field-label {
  font-size: 12px;
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.input,
.select,
.textarea {
  width: 100%;
  padding: 12px 14px;
  font-size: 14px;
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  transition: all var(--t-fast) var(--ease);
}

.input::placeholder { color: var(--text-tertiary); }

.input:focus,
.select:focus,
.textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: var(--shadow-glow);
  background: var(--surface-elevated);
}

.input.error {
  border-color: var(--danger);
}

.field-error {
  font-size: 12px;
  color: var(--danger);
  margin-top: 4px;
}

/* Card */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--sp-6);
  transition: all var(--t-default) var(--ease);
}

.card-glass {
  background: var(--surface-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.card-hoverable:hover {
  border-color: var(--border-strong);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--sp-5);
}

/* Badge */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  font-size: 11px;
  font-weight: 500;
  border-radius: var(--radius-pill);
  background: var(--surface-elevated);
  color: var(--text-secondary);
  border: 1px solid var(--border);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.badge-success {
  background: var(--success-soft);
  color: var(--success);
  border-color: transparent;
}

.badge-warning {
  background: var(--warning-soft);
  color: var(--warning);
  border-color: transparent;
}

.badge-danger {
  background: var(--danger-soft);
  color: var(--danger);
  border-color: transparent;
}

.badge-accent {
  background: var(--accent-soft);
  color: var(--accent);
  border-color: transparent;
}

/* Avatar */
.avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-pill);
  background: linear-gradient(135deg, var(--accent), #8B5CF6);
  color: white;
  font-weight: 600;
  font-size: 13px;
  flex-shrink: 0;
  letter-spacing: -0.02em;
}

.avatar-lg { width: 48px; height: 48px; font-size: 16px; }
.avatar-sm { width: 28px; height: 28px; font-size: 11px; }

/* Skeleton loading */
.skeleton {
  display: block;
  background: linear-gradient(90deg, var(--surface) 0%, var(--surface-elevated) 50%, var(--surface) 100%);
  background-size: 200% 100%;
  animation: skeleton-shimmer 1.4s ease-in-out infinite;
  border-radius: var(--radius-sm);
}

@keyframes skeleton-shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* Spinner */
.spinner {
  width: 16px;
  height: 16px;
  border: 2px solid currentColor;
  border-right-color: transparent;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  display: inline-block;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Animations */
@keyframes fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slide-up {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slide-in-right {
  from { opacity: 0; transform: translateX(20px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-6px); }
  40% { transform: translateX(6px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}

.animate-fade { animation: fade-in var(--t-default) var(--ease); }
.animate-slide-up { animation: slide-up var(--t-slow) var(--ease); }
.animate-slide-right { animation: slide-in-right var(--t-default) var(--ease); }
.animate-shake { animation: shake 0.4s var(--ease); }

/* Stagger children */
.stagger > * { animation: slide-up var(--t-slow) var(--ease) both; }
.stagger > *:nth-child(1) { animation-delay: 0ms; }
.stagger > *:nth-child(2) { animation-delay: 50ms; }
.stagger > *:nth-child(3) { animation-delay: 100ms; }
.stagger > *:nth-child(4) { animation-delay: 150ms; }
.stagger > *:nth-child(5) { animation-delay: 200ms; }
.stagger > *:nth-child(6) { animation-delay: 250ms; }
.stagger > *:nth-child(7) { animation-delay: 300ms; }
.stagger > *:nth-child(8) { animation-delay: 350ms; }

/* Layout primitives */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.justify-center { justify-content: center; }
.gap-1 { gap: var(--sp-1); }
.gap-2 { gap: var(--sp-2); }
.gap-3 { gap: var(--sp-3); }
.gap-4 { gap: var(--sp-4); }
.gap-5 { gap: var(--sp-5); }
.gap-6 { gap: var(--sp-6); }
.flex-1 { flex: 1; }

.grid { display: grid; }
.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); }

/* Toast */
#toast-container {
  position: fixed;
  top: var(--sp-5);
  right: var(--sp-5);
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
  z-index: 1000;
}

.toast {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  padding: 14px 20px;
  background: var(--surface-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  animation: slide-in-right var(--t-default) var(--ease);
  max-width: 360px;
}

.toast-success { border-left: 3px solid var(--success); }
.toast-error { border-left: 3px solid var(--danger); }
.toast-info { border-left: 3px solid var(--info); }

/* Modal */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 999;
  animation: fade-in var(--t-default) var(--ease);
}

.modal {
  background: var(--surface-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--sp-7);
  width: 90%;
  max-width: 540px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  animation: slide-up var(--t-default) var(--ease);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--sp-6);
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: var(--sp-3);
  margin-top: var(--sp-7);
}

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