/* ============================================================
   1. Design Tokens
   ============================================================ */

:root {
  /* Brand */
  --colour-brand: #5bc0de;
  --colour-brand-strong: #4097b1;
  --colour-brand-soft: #cceffa;

  /* Backgrounds */
  --colour-background: #f4f6fb;
  --colour-surface: #ffffff;
  --colour-surface-subtle: #f8f9fd;
  --colour-overlay: rgba(15, 23, 42, 0.5);

  /* Text */
  --colour-text: #1f2937;
  --colour-text-strong: #0c1016;
  --colour-text-subtle: #4b5563;
  --colour-text-muted: #6b7280;
  --colour-text-on-brand: #fff;

  /* Borders */
  --colour-border: #d5d9e3;
  --colour-border-subtle: #eaeaea;
  --colour-border-strong: #b7bdcd;

  /* Semantic states */
  --success-strong: #0f9d58;
  --danger-strong: #dc2626;
  --danger-strong-hover: #b91c1c;
  --danger-soft: #fef2f2;
  --danger-border-strong: #fca5a5;
  --warning-strong: #f59e0b;

  /* Disabled */
  --colour-button-disabled: #9ca3af;

  /* Focus */
  --focus-ring: rgba(64, 151, 177, 0.32);

  /* Spacing */
  --space-050: 4px;
  --space-100: 8px;
  --space-150: 12px;
  --space-200: 16px;
  --space-300: 24px;
  --space-400: 32px;
  --space-500: 48px;

  /* Typography */
  --font-family-sans: "Inter", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --font-family-mono: "SF Mono", "Monaco", "Inconsolata", "Fira Code", "Consolas", monospace;
  --font-size-xs: 10px;
  --font-size-sm: 14px;
  --font-size-md: 16px;
  --font-size-lg: 20px;
  --font-size-xl: 24px;
  --font-size-xxl: 32px;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --line-height-tight: 1.2;
  --line-height-normal: 1.5;

  /* Border radius */
  --radius-tiny: 3px;
  --radius-small: 6px;
  --radius-medium: 10px;
  --radius-large: 16px;

  /* YAML syntax highlighting */
  --colour-yaml-key:     #4097b1;  /* YAML keys */
  --colour-yaml-string:  #296071;  /* string values */
  --colour-yaml-literal: #0890b9;  /* booleans and null*/
  --colour-yaml-number:  #15333d;  /* numbers*/

  /* Shadows */
  --shadow-soft: 0 10px 24px rgba(15, 23, 42, 0.12);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.15);
  --shadow-overlay: 0 18px 36px rgba(15, 23, 42, 0.25);

  /* Layout */
  --layout-width: 1200px;
  --header-height: 48px;
}

/* ============================================================
   2. Reset / Base
   ============================================================ */

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

body {
  margin: 0;
  font-family: var(--font-family-sans);
  font-size: var(--font-size-md);
  line-height: var(--line-height-normal);
  color: var(--colour-text);
  background-color: var(--colour-background);
}

/* ============================================================
   3. Utility
   ============================================================ */

.hidden {
  display: none;
}

/* Buttons have display: inline-flex which outranks .hidden at equal specificity.
   This rule raises specificity to 0-2-0 so .hidden always wins on .btn elements. */
.btn.hidden {
  display: none;
}

/* ============================================================
   4. Entry Screen
   ============================================================ */

#entry-screen {
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: var(--space-400);
}

#entry-screen:not(.hidden) {
  display: flex;
}

.entry-card {
  background-color: var(--colour-surface);
  border-radius: var(--radius-medium);
  box-shadow: var(--shadow-soft);
  padding: var(--space-500);
  max-width: 480px;
  width: 100%;
}

.entry-card h1 {
  margin: 0 0 var(--space-100);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--colour-text-strong);
  line-height: var(--line-height-tight);
}

.entry-card p {
  margin: 0 0 var(--space-400);
  color: var(--colour-text-subtle);
}

.entry-actions {
  display: flex;
  gap: var(--space-200);
  margin-bottom: var(--space-300);
}

/* ============================================================
   5. Buttons
   ============================================================ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: var(--space-150) var(--space-300);
  margin: var(--space-050);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-medium);
  border: none;
  border-radius: var(--radius-small);
  cursor: pointer;
  text-decoration: none;
  transition: background-color 0.15s ease, opacity 0.15s ease;
}

.btn-primary {
  background-color: var(--colour-brand);
  color: var(--colour-text-on-brand);
}

.btn-primary:hover:not([disabled]) {
  background-color: var(--colour-brand-strong);
}

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

.btn[disabled] {
  cursor: not-allowed;
  opacity: 0.6;
}

.btn-primary[disabled] {
  background-color: var(--colour-button-disabled);
}

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

.btn-secondary:hover:not([disabled]) {
  background-color: var(--colour-surface-subtle);
}

.btn-danger {
  background-color: var(--danger-strong);
  color: var(--colour-text-on-brand);
}

.btn-danger:hover:not([disabled]) {
  background-color: var(--danger-strong-hover);
}

.btn-danger[disabled] {
  background-color: var(--colour-button-disabled);
}

.modal-actions {
  display: flex;
  gap: var(--space-200);
  margin-top: var(--space-300);
}

/* ============================================================
   6. Editor — split panel
   ============================================================ */

#editor {
  max-width: var(--layout-width);
  margin: 0 auto;
  height: 100vh;
}

#editor:not(.hidden) {
  display: flex;
}

/* ============================================================
   7. Form Panel
   ============================================================ */

#form-panel {
  flex: 1;
  height: 100vh;
  overflow-y: auto;
  padding: var(--space-400);
}

#form-panel a {
  color: var(--colour-brand);
  text-decoration: none;
}

#form-panel a:hover {
  color: var(--colour-brand-strong);
  text-decoration: none;
}

/* ============================================================
   8. YAML Panel
   ============================================================ */

#yaml-panel {
  flex: 1;
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  color: var(--colour-text);
  background-color: var(--colour-surface-subtle);
  border-left: 1px solid var(--colour-border);
  overflow-y: auto;
  padding: var(--space-200);
  white-space: pre-wrap;
}

#yaml-panel .hljs-attr              { color: var(--colour-yaml-key); }
#yaml-panel .hljs-attr.hljs-attr-top {
  color: var(--colour-text-strong);
  font-size: var(--font-size-md);
  padding-top: 20px;
  display: inline-block;
}
#yaml-panel .hljs-string  { color: var(--colour-yaml-string); }
#yaml-panel .hljs-literal { color: var(--colour-yaml-literal); }
#yaml-panel .hljs-number  { color: var(--colour-yaml-number); }
#yaml-panel .hljs-comment { color: var(--colour-text-muted); font-style: italic; }

/* ============================================================
   9. Form Fields
   ============================================================ */

.field-wrapper {
  display: flex;
  flex-direction: column;
  gap: var(--space-050);
  margin-bottom: var(--space-300);
}

.radio-group {
  display: flex;
  gap: var(--space-300);
}

label {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--colour-text-strong);
  display: block;
}

input[type="text"],
input[type="file"],
select {
  min-height: 44px;
  padding: var(--space-100) var(--space-150);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-md);
  color: var(--colour-text);
  background-color: var(--colour-surface);
  border: 1px solid var(--colour-border);
  border-radius: var(--radius-small);
  width: 100%;
}

input[type="text"]:focus-visible,
select:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

input[type="text"]:hover:not([disabled]),
input[type="file"]:hover:not([disabled]),
select:hover:not([disabled]) {
  border-color: var(--colour-border-strong);
}

input[type="text"][disabled],
input[type="file"][disabled],
select[disabled] {
  cursor: not-allowed;
  opacity: 0.6;
}

fieldset p {
  font-size: var(--font-size-sm);
}

.field-wrapper.error input,
.field-wrapper.error select {
  border-color: var(--danger-strong);
}

.field-preview {
  font-size: var(--font-size-sm);
  color: var(--colour-text-subtle);
  font-family: var(--font-family-mono);
}

.field-error {
  font-size: var(--font-size-sm);
  color: var(--danger-strong);
}

/* ============================================================
   10. Modal
   ============================================================ */

#modal,
#command-modal {
  position: fixed;
  inset: 0;
  background-color: var(--colour-overlay);
  align-items: center;
  justify-content: center;
  z-index: 100;
}

#modal:not(.hidden),
#command-modal:not(.hidden) {
  display: flex;
}

.modal-card {
  background-color: var(--colour-surface);
  border-radius: var(--radius-large);
  box-shadow: var(--shadow-overlay);
  padding: var(--space-400);
  max-width: 480px;
  width: 100%;
}

.modal-safety-note {
  font-size: var(--font-size-sm);
  font-style: italic;
  color: var(--colour-text-muted);
  margin: 0;
  margin-bottom: var(--space-100);
}

/* ============================================================
   11. Responsive — collapse split panel below 1024px
   ============================================================ */

@media (max-width: 1024px) {
  #editor {
    flex-direction: column;
  }

  #yaml-panel {
    border-left: none;
    border-top: 1px solid var(--colour-border);
  }
}

/* ============================================================
   12. App Header and Documentation Modal
   ============================================================ */

#app-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background-color: var(--colour-brand);
  padding: var(--space-100) var(--space-300);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.app-header-logo {
  height: var(--space-300);
}

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--space-200);
}

.docs-btn {
  background: none;
  border: none;
  color: var(--colour-text-on-brand);
  cursor: pointer;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
}

.docs-btn:hover {
  color: var(--colour-brand-soft);
}

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

.docs-btn[disabled] {
  opacity: 0.6;
  cursor: not-allowed;
}

.about-btn {
  background: none;
  border: none;
  color: var(--colour-text-on-brand);
  cursor: pointer;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
}

.about-btn:hover {
  color: var(--colour-brand-soft);
}

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

.app-version {
  color: var(--colour-text-on-brand);
  font-size: var(--font-size-sm);
  opacity: 0.5;
}

#about-modal {
  position: fixed;
  inset: 0;
  background-color: var(--colour-overlay);
  align-items: center;
  justify-content: center;
  z-index: 200;
}

#about-modal:not(.hidden) {
  display: flex;
}

#form-panel,
#yaml-panel {
  margin-top: var(--header-height);
}

#docs-modal {
  position: fixed;
  inset: 0;
  z-index: 200;
  background-color: var(--colour-overlay);
  align-items: flex-start;
  justify-content: center;
}

#docs-modal:not(.hidden) {
  display: flex;
}

.docs-modal-card {
  background-color: var(--colour-surface);
  width: 100%;
  max-width: 860px;
  height: 100vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-overlay);
}

.docs-modal-header {
  display: flex;
  align-items: center;
  gap: var(--space-200);
  border-bottom: 1px solid var(--colour-border);
  padding: var(--space-100) var(--space-300);
}

.docs-modal-tabs {
  display: flex;
  align-items: center;
  gap: var(--space-100);
}
.docs-examples-tabs {
  margin-left: auto;
}
.docs-examples-label {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  color: var(--colour-text-subtle);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0 var(--space-050);
}

.docs-modal-tabs button {
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-100) var(--space-200);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--colour-text-subtle);
  border-bottom: 2px solid transparent;
}

.docs-modal-tabs button.active {
  color: var(--colour-brand);
  border-bottom-color: var(--colour-brand);
}

.docs-modal-tabs button:hover {
  color: var(--colour-brand-strong);
}

.docs-modal-tabs button:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

.docs-modal-tabs button[disabled] {
  opacity: 0.6;
  cursor: not-allowed;
}

#docs-modal-content {
  overflow-y: auto;
  padding: var(--space-300) var(--space-500);
  font-family: var(--font-family-sans);
  flex: 1;
}

body.modal-open {
  overflow: hidden;
}

/* ============================================================
   13. Docs Modal — Prose Typography
   ============================================================ */

#docs-modal-content h1,
#docs-modal-content h2,
#about-modal h2,
#docs-modal-content h3,
#docs-modal-content h4,
#docs-modal-content h5,
#docs-modal-content h6 {
  color: var(--colour-text-strong);
  font-weight: var(--font-weight-semibold);
  line-height: var(--line-height-tight);
  margin: var(--space-300) 0 var(--space-100);
}

#docs-modal-content h1 { font-size: var(--font-size-xxl); }
#docs-modal-content h2, #about-modal h2 { font-size: var(--font-size-xl); }
#docs-modal-content h3 { font-size: var(--font-size-lg); }
#docs-modal-content h4 { font-size: var(--font-size-md); }

#docs-modal-content p, #about-modal p {
  margin: 0 0 var(--space-200);
  line-height: var(--line-height-normal);
}

#docs-modal-content a, #about-modal a {
  color: var(--colour-brand);
  text-decoration: none;
}

#docs-modal-content a:hover, #about-modal a:hover {
  color: var(--colour-brand-strong);
  text-decoration: none;
}

#docs-modal-content code {
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  background-color: var(--colour-surface-subtle);
  padding: 0 var(--space-050);
  border-radius: var(--radius-tiny);
}

#docs-modal-content pre {
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  background-color: var(--colour-surface-subtle);
  border: 1px solid var(--colour-border-subtle);
  border-radius: var(--radius-small);
  padding: var(--space-200);
  overflow-x: auto;
  margin: 0 0 var(--space-200);
}

#docs-modal-content pre code {
  background: none;
  padding: 0;
}

#docs-modal-content ul,
#docs-modal-content ol {
  padding-left: var(--space-400);
  margin: 0 0 var(--space-200);
}

#docs-modal-content li {
  margin-bottom: var(--space-050);
}

#docs-modal-content blockquote {
  border-left: 3px solid var(--colour-brand-soft);
  padding-left: var(--space-200);
  margin: 0 0 var(--space-200);
  color: var(--colour-text-subtle);
  font-style: italic;
}

#docs-modal-content hr {
  border: none;
  border-top: 1px solid var(--colour-border);
  margin: var(--space-300) 0;
}

#docs-modal-content table {
  border-collapse: collapse;
  width: 100%;
  margin: 0 0 var(--space-200);
}

#docs-modal-content th,
#docs-modal-content td {
  border: 1px solid var(--colour-border);
  padding: var(--space-100) var(--space-150);
  text-align: left;
}

#docs-modal-content th {
  background-color: var(--colour-surface-subtle);
  font-weight: var(--font-weight-semibold);
}

/* ============================================================
   14. Docs modal — examples hamburger (hidden by default on desktop)
   ============================================================ */

#docs-examples-hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  font-size: var(--font-size-md);
  color: var(--colour-text-subtle);
  padding: var(--space-050) var(--space-100);
  margin-left: auto;
  line-height: 1;
}

#docs-examples-hamburger:hover {
  color: var(--colour-brand-strong);
}

#docs-examples-hamburger:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

#docs-examples-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  right: var(--space-300);
  background-color: var(--colour-surface);
  border: 1px solid var(--colour-border);
  border-radius: var(--radius-small);
  box-shadow: var(--shadow-md);
  z-index: 10;
  min-width: 120px;
}

#docs-examples-dropdown.open {
  display: flex;
  flex-direction: column;
}

.docs-examples-dropdown-title {
  display: block;
  padding: var(--space-100) var(--space-200) var(--space-050);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  color: var(--colour-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  border-bottom: 1px solid var(--colour-border-subtle);
  margin-bottom: var(--space-050);
}

#docs-examples-dropdown button {
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-100) var(--space-200);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--colour-text-subtle);
  text-align: left;
}

#docs-examples-dropdown button:hover {
  color: var(--colour-brand-strong);
  background-color: var(--colour-surface-subtle);
}

#docs-examples-dropdown button.active {
  color: var(--colour-brand);
}

#docs-examples-dropdown button:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

/* ============================================================
   15. Responsive — docs modal header below 600px
   ============================================================ */

@media (max-width: 780px) {
  .docs-modal-header {
    position: relative;
  }

  .docs-examples-tabs {
    display: none;
  }

  #docs-examples-hamburger {
    display: flex;
    align-items: center;
  }

  .docs-modal-tabs button {
    padding: var(--space-050) var(--space-100);
    font-size: var(--font-size-sm);
  }

  #docs-modal-content pre {
    white-space: pre-wrap;
    overflow-wrap: break-word;
    overflow-x: hidden;
  }
}