/* Proof Before Green — Evidence Explorer Design System
   Conforms to PROJECT_HANDOFF.md Section 10 Design Brief:
   - Light neutral background, restrained status colors, readable typography
   - Responsive (390px mobile to 1440px desktop)
   - Accessible keyboard focus and high-contrast text
*/

:root {
  --bg-app: #f8fafc;
  --bg-card: #ffffff;
  --bg-subtle: #f1f5f9;
  --bg-code: #0f172a;
  
  --border-light: #e2e8f0;
  --border-medium: #cbd5e1;
  --border-focus: #3b82f6;

  --text-main: #0f172a;
  --text-muted: #475569;
  --text-subtle: #64748b;
  --text-inverse: #f8fafc;

  /* Restrained semantic status tokens */
  --pass-text: #065f46;
  --pass-bg: #ecfdf5;
  --pass-border: #a7f3d0;
  --pass-accent: #059669;

  --fail-text: #991b1b;
  --fail-bg: #fef2f2;
  --fail-border: #fecaca;
  --fail-accent: #dc2626;

  --blocked-text: #92400e;
  --blocked-bg: #fffbeb;
  --blocked-border: #fde68a;
  --blocked-accent: #d97706;

  --info-text: #1e40af;
  --info-bg: #eff6ff;
  --info-border: #bfdbfe;
  --info-accent: #2563eb;

  --code-text: #e2e8f0;

  /* Tables & Defect Highlights */
  --table-row-hover: #f1f5f9;
  --defect-row-bg: #fef2f2;
  --defect-row-hover: #fee2e2;

  /* Diff Viewer Tokens */
  --diff-bg: #ffffff;
  --diff-add-bg: #e6ffed;
  --diff-add-text: #1a7f37;
  --diff-del-bg: #ffebe9;
  --diff-del-text: #cf222e;
  --diff-hunk-bg: #f0f6fc;
  --diff-hunk-text: #6e7781;

  /* Buttons */
  --btn-primary-bg: #2563eb;
  --btn-primary-text: #ffffff;
  --btn-primary-hover: #1d4ed8;

  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.07), 0 2px 4px -2px rgb(0 0 0 / 0.07);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

/* Dark Theme Variables */
[data-theme="dark"] {
  --bg-app: #0b1120;
  --bg-card: #151e32;
  --bg-subtle: #1e293b;
  --bg-code: #0a0f1d;
  --code-text: #e2e8f0;

  --border-light: #223049;
  --border-medium: #334155;
  --border-focus: #60a5fa;

  --text-main: #f8fafc;
  --text-muted: #cbd5e1;
  --text-subtle: #94a3b8;
  --text-inverse: #0f172a;

  /* Restrained semantic status tokens in dark mode - high contrast */
  --pass-text: #34d399;
  --pass-bg: rgba(5, 150, 105, 0.18);
  --pass-border: rgba(52, 211, 153, 0.35);
  --pass-accent: #10b981;

  --fail-text: #f87171;
  --fail-bg: rgba(220, 38, 38, 0.18);
  --fail-border: rgba(248, 113, 113, 0.35);
  --fail-accent: #ef4444;

  --blocked-text: #fbbf24;
  --blocked-bg: rgba(217, 119, 6, 0.18);
  --blocked-border: rgba(251, 191, 36, 0.35);
  --blocked-accent: #f59e0b;

  --info-text: #93c5fd;
  --info-bg: rgba(37, 99, 235, 0.2);
  --info-border: rgba(147, 197, 253, 0.35);
  --info-accent: #60a5fa;

  /* Tables & Defect Highlights */
  --table-row-hover: #1e293b;
  --defect-row-bg: rgba(239, 68, 68, 0.14);
  --defect-row-hover: rgba(239, 68, 68, 0.22);

  /* Diff Viewer Tokens */
  --diff-bg: #0f172a;
  --diff-add-bg: rgba(16, 185, 129, 0.18);
  --diff-add-text: #4ade80;
  --diff-del-bg: rgba(239, 68, 68, 0.18);
  --diff-del-text: #f87171;
  --diff-hunk-bg: #1e293b;
  --diff-hunk-text: #94a3b8;

  /* Buttons */
  --btn-primary-bg: #3b82f6;
  --btn-primary-text: #ffffff;
  --btn-primary-hover: #2563eb;

  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4), 0 2px 4px -2px rgb(0 0 0 / 0.4);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]):not([data-theme="dark"]) {
    --bg-app: #0b1120;
    --bg-card: #151e32;
    --bg-subtle: #1e293b;
    --bg-code: #0a0f1d;
    --code-text: #e2e8f0;

    --border-light: #223049;
    --border-medium: #334155;
    --border-focus: #60a5fa;

    --text-main: #f8fafc;
    --text-muted: #cbd5e1;
    --text-subtle: #94a3b8;
    --text-inverse: #0f172a;

    --pass-text: #34d399;
    --pass-bg: rgba(5, 150, 105, 0.18);
    --pass-border: rgba(52, 211, 153, 0.35);
    --pass-accent: #10b981;

    --fail-text: #f87171;
    --fail-bg: rgba(220, 38, 38, 0.18);
    --fail-border: rgba(248, 113, 113, 0.35);
    --fail-accent: #ef4444;

    --blocked-text: #fbbf24;
    --blocked-bg: rgba(217, 119, 6, 0.18);
    --blocked-border: rgba(251, 191, 36, 0.35);
    --blocked-accent: #f59e0b;

    --info-text: #93c5fd;
    --info-bg: rgba(37, 99, 235, 0.2);
    --info-border: rgba(147, 197, 253, 0.35);
    --info-accent: #60a5fa;

    --table-row-hover: #1e293b;
    --defect-row-bg: rgba(239, 68, 68, 0.14);
    --defect-row-hover: rgba(239, 68, 68, 0.22);

    --diff-bg: #0f172a;
    --diff-add-bg: rgba(16, 185, 129, 0.18);
    --diff-add-text: #4ade80;
    --diff-del-bg: rgba(239, 68, 68, 0.18);
    --diff-del-text: #f87171;
    --diff-hunk-bg: #1e293b;
    --diff-hunk-text: #94a3b8;

    --btn-primary-bg: #3b82f6;
    --btn-primary-text: #ffffff;
    --btn-primary-hover: #2563eb;

    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4), 0 2px 4px -2px rgb(0 0 0 / 0.4);
  }
}

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

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

code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--bg-subtle);
  color: var(--text-main);
  padding: 0.15em 0.35em;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-light);
}

pre code, .code-block code {
  background: none;
  border: none;
  padding: 0;
  color: inherit;
}

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 10px;
  background: var(--text-main);
  color: var(--text-inverse);
  padding: 8px;
  z-index: 1000;
  transition: top 0.2s;
  text-decoration: none;
  border-radius: var(--radius-sm);
}
.skip-link:focus {
  top: 10px;
}

/* Header & Banner */
header.app-header {
  background: var(--bg-card);
  border-bottom: 1px solid var(--border-light);
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow-sm);
}

.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
}

.brand-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.brand-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.brand-title .logo-badge {
  background: var(--info-bg);
  color: var(--info-accent);
  border: 1px solid var(--info-border);
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.brand-subtitle {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-top: 0.15rem;
}

.header-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

.theme-switch {
  display: inline-flex;
  align-items: center;
  background: var(--bg-subtle);
  border: 1px solid var(--border-medium);
  border-radius: 9999px;
  padding: 2px;
  gap: 2px;
}

.theme-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.55rem;
  border-radius: 9999px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  transition: all 0.15s ease-in-out;
  line-height: 1;
}

.theme-btn:hover {
  color: var(--text-main);
}

.theme-btn:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 1px;
}

.theme-btn.active {
  background: var(--bg-card);
  color: var(--text-main);
  box-shadow: var(--shadow-sm);
}

[data-theme="dark"] .theme-btn.active {
  background: var(--bg-card);
  color: var(--text-main);
  border: 1px solid var(--border-light);
}

.status-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.pill {
  font-size: 0.8125rem;
  font-weight: 600;
  padding: 0.28rem 0.75rem;
  border-radius: 9999px;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  line-height: 1.3;
}
a.pill {
  text-decoration: none;
  cursor: pointer;
  transition: filter 0.15s ease, transform 0.15s ease;
}
a.pill:hover {
  filter: brightness(1.08);
  text-decoration: none;
}
.pill-pass { background: var(--pass-bg); color: var(--pass-text); border: 1px solid var(--pass-border); }
.pill-fail { background: var(--fail-bg); color: var(--fail-text); border: 1px solid var(--fail-border); }
.pill-blocked { background: var(--blocked-bg); color: var(--blocked-text); border: 1px solid var(--blocked-border); }
.pill-neutral { background: var(--bg-subtle); color: var(--text-muted); border: 1px solid var(--border-light); }

/* Navigation Tabs */
nav.app-tabs {
  margin-top: 0.75rem;
  border-top: 1px solid var(--border-light);
  display: flex;
  overflow-x: auto;
  gap: 0.25rem;
  padding-top: 0.25rem;
  scrollbar-width: thin;
}

.tab-btn {
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  padding: 0.65rem 1rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s ease-in-out;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}

.tab-btn:hover {
  color: var(--text-main);
  background: var(--bg-subtle);
}

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

.tab-btn.active {
  color: var(--info-accent);
  border-bottom-color: var(--info-accent);
  background: var(--info-bg);
}

/* Main Container */
main.app-main {
  max-width: 1280px;
  width: 100%;
  margin: 1.5rem auto;
  padding: 0 1.5rem;
  flex: 1;
}

.tab-panel {
  display: none;
}
.tab-panel.active {
  display: block;
  animation: fadeIn 0.2s ease-in-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(2px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Cards & Layout */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  box-shadow: var(--shadow-sm);
  margin-bottom: 1.25rem;
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-light);
}

.card-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-main);
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.25rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

/* KPI Chips */
.kpi-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 1rem;
  box-shadow: var(--shadow-sm);
}
.kpi-label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-subtle);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.kpi-value {
  font-size: 1.375rem;
  font-weight: 700;
  margin-top: 0.35rem;
  color: var(--text-main);
  line-height: 1.25;
}
.kpi-sub {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-top: 0.35rem;
  line-height: 1.35;
}

/* Timeline */
.timeline {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  position: relative;
  padding-left: 1.5rem;
}
.timeline::before {
  content: "";
  position: absolute;
  left: 0.5rem;
  top: 0.5rem;
  bottom: 0.5rem;
  width: 2px;
  background: var(--border-medium);
}
.timeline-item {
  position: relative;
}
.timeline-dot {
  position: absolute;
  left: -1.35rem;
  top: 0.25rem;
  width: 0.75rem;
  height: 0.75rem;
  border-radius: 50%;
  background: var(--info-accent);
  border: 2px solid var(--bg-card);
}
.timeline-dot.failed { background: var(--fail-accent); }
.timeline-dot.success { background: var(--pass-accent); }
.timeline-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-main);
}
.timeline-meta {
  font-size: 0.75rem;
  color: var(--text-subtle);
  margin-bottom: 0.25rem;
  font-family: var(--font-mono);
}
.timeline-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Table styles */
.data-table-container {
  overflow-x: auto;
}
table.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
  text-align: left;
}
table.data-table th, table.data-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-light);
}
table.data-table th {
  background: var(--bg-subtle);
  font-weight: 600;
  color: var(--text-muted);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
table.data-table tbody tr:hover {
  background: var(--table-row-hover);
}

tr.row-defect-highlight {
  background: var(--defect-row-bg);
}

table.data-table tbody tr.row-defect-highlight:hover {
  background: var(--defect-row-hover);
}

/* Stepper / Replay View */
.replay-container {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}
.replay-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--bg-subtle);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-light);
}
.step-indicators {
  display: flex;
  gap: 0.5rem;
}
.step-bullet {
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  border: 1px solid var(--border-medium);
  background: var(--bg-card);
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s ease-in-out;
}
.step-bullet.active {
  background: var(--info-accent);
  color: white;
  border-color: var(--info-accent);
}
.step-bullet.defect {
  border-color: var(--fail-accent);
  color: var(--fail-accent);
}
.step-bullet.active.defect {
  background: var(--fail-accent);
  color: white;
}

.step-details-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}
@media (max-width: 768px) {
  .step-details-grid {
    grid-template-columns: 1fr;
  }
}

.code-block {
  background: var(--bg-code);
  color: var(--code-text);
  padding: 1rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-light);
  font-family: var(--font-mono);
  font-size: 0.825rem;
  overflow-x: auto;
  line-height: 1.45;
}

.state-box {
  background: var(--bg-subtle);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 1rem;
}
.state-box-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-subtle);
  margin-bottom: 0.5rem;
}

/* Diff viewer */
.diff-container {
  font-family: var(--font-mono);
  font-size: 0.825rem;
  background: var(--diff-bg);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  overflow-x: auto;
}
.diff-line {
  padding: 0.15rem 0.5rem;
  white-space: pre-wrap;
  display: flex;
}
.diff-add {
  background: var(--diff-add-bg);
  color: var(--diff-add-text);
}
.diff-del {
  background: var(--diff-del-bg);
  color: var(--diff-del-text);
}
.diff-hunk {
  background: var(--diff-hunk-bg);
  color: var(--diff-hunk-text);
  font-weight: 600;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.15s ease-in-out;
  text-decoration: none;
}
.btn-primary {
  background: var(--btn-primary-bg);
  color: var(--btn-primary-text);
}
.btn-primary:hover {
  background: var(--btn-primary-hover);
}
.btn-secondary {
  background: var(--bg-card);
  color: var(--text-main);
  border-color: var(--border-medium);
}
.btn-secondary:hover {
  background: var(--bg-subtle);
}

/* Form controls */
select, .form-select {
  background-color: var(--bg-card);
  color: var(--text-main);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-sm);
  padding: 0.35rem 0.65rem;
  font-size: 0.85rem;
  font-family: inherit;
}

select:focus, .form-select:focus {
  outline: 2px solid var(--border-focus);
  border-color: var(--border-focus);
}

option {
  background-color: var(--bg-card);
  color: var(--text-main);
}

/* Compact Neutral Case Study Panel */
.case-study-panel {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-left: 4px solid var(--border-medium);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  margin-bottom: 1.25rem;
  box-shadow: var(--shadow-sm);
}

.case-study-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-main);
  margin: 0 0 0.5rem 0;
  letter-spacing: -0.01em;
}

.case-study-body {
  font-size: 0.9125rem;
  line-height: 1.55;
  color: var(--text-main);
  margin: 0 0 0.75rem 0;
}

.case-study-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem 0.85rem;
  font-size: 0.8125rem;
  color: var(--text-muted);
  padding-top: 0.65rem;
  border-top: 1px solid var(--border-light);
}

.case-study-meta a {
  color: var(--info-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
  font-weight: 600;
}

.case-study-meta a:hover {
  color: var(--border-focus);
}

.case-study-meta .meta-divider {
  color: var(--border-medium);
}

/* Callout banner */
.callout {
  border-left: 4px solid var(--info-accent);
  background: var(--info-bg);
  padding: 1rem;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin-bottom: 1.25rem;
  font-size: 0.875rem;
}
.callout-warning {
  border-left-color: var(--blocked-accent);
  background: var(--blocked-bg);
  color: var(--blocked-text);
}
.callout-error {
  border-left-color: var(--fail-accent);
  background: var(--fail-bg);
  color: var(--fail-text);
}
.callout-success {
  border-left-color: var(--pass-accent);
  background: var(--pass-bg);
  color: var(--pass-text);
}

/* Footer */
footer.app-footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border-light);
  padding: 1.5rem;
  margin-top: auto;
  font-size: 0.8rem;
  color: var(--text-subtle);
}
.footer-inner {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

/* Responsive adjustments */
@media (max-width: 640px) {
  .header-inner {
    padding: 0.75rem 1rem;
  }
  main.app-main {
    padding: 0 1rem;
  }
  .brand-row {
    flex-direction: column;
    align-items: flex-start;
  }
  .theme-btn .theme-text {
    display: none;
  }
  .theme-btn {
    padding: 0.3rem 0.45rem;
  }
}