/* ============================================================
   CSS CUSTOM PROPERTIES
   ============================================================ */
:root {
  --nav-height: 50px;
  --max-width: 960px;

  --bg-primary: #ffffff;
  --bg-secondary: #f5f5f5;
  --bg-nav: rgba(26, 26, 26, 0.75);
  --bg-footer: #1a1a1a;
  --text-primary: #222;
  --text-body: #333;
  --text-muted: #555;
  --text-subtle: #777;
  --text-faint: #999;
  --text-nav: #ccc;
  --text-nav-hover: #fff;
  --border-light: #e4e4e4;
  --card-bg: #ffffff;
  --input-bg: #f9f9f9;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --edge-color: #dc2626;
  --edge-bg: #fef2f2;

  --font-serif: 'EB Garamond', serif;
  --font-sans: 'Quattrocento Sans', sans-serif;
  --font-mono: 'SF Mono', 'Menlo', 'Consolas', monospace;
}

/* ============================================================
   DARK MODE
   ============================================================ */
[data-theme="dark"] {
  --bg-primary: #1a1a1a;
  --bg-secondary: #242424;
  --bg-nav: rgba(10, 10, 10, 0.85);
  --bg-footer: #111;
  --text-primary: #e8e8e8;
  --text-body: #d4d4d4;
  --text-muted: #aaa;
  --text-subtle: #888;
  --text-faint: #666;
  --border-light: #3a3a3a;
  --card-bg: #242424;
  --input-bg: #2a2a2a;
  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --edge-color: #f87171;
  --edge-bg: #3b1111;
}

/* ============================================================
   RESET
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  padding-top: var(--nav-height);
  font-family: var(--font-sans);
  color: var(--text-body);
  background-color: var(--bg-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

h1, h2, h3, h4 { margin: 0; line-height: 1.3; }
p { margin: 0; }
a { color: inherit; text-decoration: none; }

/* ============================================================
   NAVBAR
   ============================================================ */
.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background-color: var(--bg-nav);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  min-height: var(--nav-height);
  padding: 0 16px;
  gap: 12px;
}

.nav-back {
  color: var(--text-nav);
  font-size: 14px;
  font-family: var(--font-sans);
  transition: color 0.2s;
  white-space: nowrap;
}

.nav-back::before { content: '\2190 '; }
.nav-back:hover { color: var(--text-nav-hover); }

.nav-title {
  flex: 1;
  text-align: center;
  color: var(--text-nav-hover);
  font-family: var(--font-serif);
  font-size: 16px;
  font-weight: 600;
}

.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 20px;
  padding: 6px;
  line-height: 1;
  transition: transform 0.3s;
}

.theme-toggle:hover { transform: rotate(20deg); }

/* ============================================================
   LAYOUT
   ============================================================ */
.container {
  max-width: var(--max-width);
  width: 90%;
  margin: 0 auto;
  padding: 32px 16px 48px;
  flex: 1;
}

/* ============================================================
   HEADER
   ============================================================ */
.app-header {
  text-align: center;
  margin-bottom: 28px;
}

.app-header h1 {
  font-family: var(--font-serif);
  font-size: 2.6rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.subtitle {
  font-size: 17px;
  color: var(--text-muted);
}

/* ============================================================
   CARDS
   ============================================================ */
.card {
  background-color: var(--card-bg);
  border: 1.5px solid var(--border-light);
  border-radius: 12px;
  padding: 24px;
  margin-bottom: 20px;
}

/* ============================================================
   MODE TOGGLE
   ============================================================ */
.mode-card {
  text-align: center;
}

.mode-toggle {
  display: inline-flex;
  border: 1.5px solid var(--border-light);
  border-radius: 10px;
  overflow: hidden;
  margin-bottom: 12px;
}

.mode-btn {
  padding: 12px 32px;
  border: none;
  background: none;
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 700;
  color: var(--text-muted);
  cursor: pointer;
  transition: background-color 0.2s, color 0.2s;
}

.mode-btn:hover {
  color: var(--text-primary);
}

.mode-btn.active {
  background-color: var(--text-primary);
  color: var(--bg-primary);
}

.mode-btn.active[data-mode="edge"] {
  background-color: var(--edge-color);
  color: #fff;
}

.mode-desc {
  font-size: 14px;
  color: var(--text-subtle);
}

/* ============================================================
   CONFIG
   ============================================================ */
.config-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}

.config-header .input-label {
  margin-bottom: 0;
}

.input-label {
  display: block;
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.config-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 18px;
}

.field-group {
  display: flex;
  flex-direction: column;
}

label {
  display: block;
  font-size: 14px;
  font-weight: 700;
  color: var(--text-muted);
  margin-bottom: 6px;
}

input[type="number"],
select {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--border-light);
  border-radius: 8px;
  background-color: var(--input-bg);
  color: var(--text-body);
  font-family: var(--font-sans);
  font-size: 14px;
  outline: none;
  transition: border-color 0.2s;
}

input[type="number"]:focus,
select:focus {
  border-color: var(--text-subtle);
}

/* ============================================================
   CHECKBOX GRID
   ============================================================ */
.checkbox-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 8px;
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 400;
  color: var(--text-body);
  cursor: pointer;
  margin-bottom: 0;
}

.checkbox-label input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
  cursor: pointer;
}

.select-all-btn {
  background: none;
  border: none;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
  padding: 0;
  font-family: var(--font-sans);
}

.select-all-btn:hover {
  text-decoration: underline;
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border: 1.5px solid var(--border-light);
  border-radius: 8px;
  background-color: var(--bg-primary);
  color: var(--text-body);
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: background-color 0.2s, color 0.2s, border-color 0.2s, transform 0.1s;
}

.btn:hover {
  border-color: var(--text-subtle);
  transform: translateY(-1px);
}

.btn:active { transform: translateY(0); }

.btn--primary {
  background-color: var(--text-primary);
  color: var(--bg-primary);
  border-color: var(--text-primary);
  width: 100%;
  margin-top: 18px;
}

.btn--primary:hover {
  opacity: 0.9;
  border-color: var(--text-primary);
}

.btn--primary.edge-mode {
  background-color: var(--edge-color);
  border-color: var(--edge-color);
  color: #fff;
}

.btn--small { padding: 8px 16px; font-size: 13px; }

.btn--ghost {
  background: none;
  border-color: transparent;
  color: var(--text-subtle);
}

.btn--ghost:hover {
  color: var(--text-primary);
  border-color: transparent;
}

.btn--accent {
  background-color: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.btn--accent:hover {
  background-color: var(--accent-hover);
  border-color: var(--accent-hover);
}

[data-theme="dark"] .btn--primary {
  background-color: #e8e8e8;
  color: #1a1a1a;
  border-color: #e8e8e8;
}

[data-theme="dark"] .btn--primary.edge-mode {
  background-color: var(--edge-color);
  border-color: var(--edge-color);
  color: #fff;
}

/* ============================================================
   OUTPUT
   ============================================================ */
.output-section { display: none; }
.output-section.is-visible { display: block; }

.output-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
  flex-wrap: wrap;
  gap: 10px;
}

.output-header h2 {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-primary);
}

.output-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.output-stats {
  font-size: 13px;
  color: var(--text-faint);
  margin-bottom: 12px;
}

.output-body {
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-body);
  background-color: var(--input-bg);
  border: 1.5px solid var(--border-light);
  border-radius: 8px;
  padding: 20px;
  max-height: 600px;
  overflow-y: auto;
}

.output-body.mono {
  font-family: var(--font-mono);
  white-space: pre-wrap;
  word-wrap: break-word;
  tab-size: 2;
}

/* ============================================================
   COPY TOAST
   ============================================================ */
.copy-toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background-color: var(--text-primary);
  color: var(--bg-primary);
  padding: 10px 24px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 700;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s;
}

.copy-toast.is-visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ============================================================
   REFERENCE CARD
   ============================================================ */
.reference-toggle {
  cursor: pointer;
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  list-style: none;
  user-select: none;
}

.reference-toggle::-webkit-details-marker { display: none; }
.reference-toggle::before { content: '+ '; font-weight: 700; }
details[open] .reference-toggle::before { content: '\2212 '; }

.reference-body {
  margin-top: 16px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.ref-group h3 {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.ref-group p {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ============================================================
   FOOTER
   ============================================================ */
footer {
  background-color: var(--bg-footer);
  color: #aaa;
  text-align: center;
  padding: 14px 20px;
  font-size: 14px;
  font-family: var(--font-sans);
}

footer a {
  color: #ccc;
  text-decoration: underline;
  transition: color 0.2s;
}

footer a:hover { color: #fff; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 768px) {
  .app-header h1 { font-size: 2rem; }
  .card { padding: 18px; }
  .config-row { grid-template-columns: 1fr; }
  .reference-body { grid-template-columns: 1fr; }
  .checkbox-grid { grid-template-columns: repeat(2, 1fr); }
  .nav-title { font-size: 14px; }
  .mode-btn { padding: 10px 20px; font-size: 14px; }

  .output-header {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* ============================================================
   FOCUS VISIBLE (keyboard accessibility)
   ============================================================ */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.2);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}