/* ===== CSS Custom Properties ===== */
:root {
  --c-bg: #faf9f7;
  --c-surface: #ffffff;
  --c-surface-alt: #f3f1ed;
  --c-border: #dedad4;
  --c-border-strong: #c2bbb2;
  --c-text: #1e1c18;
  --c-text-muted: #6b6560;
  --c-text-light: #918c85;
  --c-primary: #2b5ce6;
  --c-primary-hover: #1e45b8;
  --c-primary-light: #eef2ff;
  --c-accent: #d4760a;
  --c-success: #1a7a3d;
  --c-error: #c0392b;
  --c-error-bg: #fdf0ef;
  --radius-sm: 6px;
  --radius: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow: 0 2px 8px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.10);
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Fira Mono', 'Roboto Mono', monospace;
  --max-width: 1160px;
  --header-height: 56px;
  --transition: 0.2s ease;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { font-family: var(--font); color: var(--c-text); background: var(--c-bg); line-height: 1.6; min-height: 100vh; }
img, svg { display: block; max-width: 100%; }
a { color: var(--c-primary); text-decoration: none; }
a:hover { text-decoration: underline; }
ul, ol { list-style: none; }
address { font-style: normal; line-height: 1.5; }
button, input, select { font: inherit; color: inherit; }

/* ===== Utility ===== */
.container { width: 100%; max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

/* ===== Header ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--c-surface);
  border-bottom: 1px solid var(--c-border);
  height: var(--header-height);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: 16px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1rem;
  color: var(--c-text);
  white-space: nowrap;
}
.logo:hover { text-decoration: none; }
.logo svg { color: var(--c-primary); flex-shrink: 0; }

.main-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}
.main-nav a {
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  color: var(--c-text-muted);
  transition: background var(--transition), color var(--transition);
}
.main-nav a:hover,
.main-nav a:focus-visible {
  background: var(--c-surface-alt);
  color: var(--c-text);
  text-decoration: none;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--c-text);
  border-radius: 1px;
  transition: transform var(--transition), opacity var(--transition);
}

/* ===== Hero ===== */
.hero {
  padding: 48px 0 32px;
}
.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 800;
  line-height: 1.2;
  max-width: 600px;
}
.hero-sub {
  font-size: 1.0625rem;
  color: var(--c-text-muted);
  margin-top: 12px;
  max-width: 520px;
}

/* ===== Formatter Grid ===== */
.formatter-grid {
  padding: 16px 0 48px;
}
.grid-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  align-items: start;
}

.panel-title {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: 16px;
}

/* ===== Form ===== */
.form-panel {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
}
.field {
  margin-bottom: 16px;
}
.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--c-text-muted);
  margin-bottom: 4px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
input, select {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--c-border-strong);
  border-radius: var(--radius-sm);
  background: var(--c-bg);
  transition: border-color var(--transition), box-shadow var(--transition);
}
input:focus, select:focus {
  outline: none;
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px var(--c-primary-light);
}
input.input-error {
  border-color: var(--c-error);
  background: var(--c-error-bg);
}
.hint {
  display: block;
  font-size: 0.75rem;
  color: var(--c-text-light);
  margin-top: 4px;
}
.field-error {
  display: block;
  font-size: 0.75rem;
  color: var(--c-error);
  margin-top: 4px;
  min-height: 1.2em;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  border: 2px solid transparent;
  transition: background var(--transition), border-color var(--transition), color var(--transition), box-shadow var(--transition);
}
.btn-primary {
  background: var(--c-primary);
  color: #fff;
  border-color: var(--c-primary);
}
.btn-primary:hover { background: var(--c-primary-hover); border-color: var(--c-primary-hover); text-decoration: none; color: #fff; }
.btn-secondary {
  background: var(--c-surface-alt);
  color: var(--c-text);
  border-color: var(--c-border-strong);
}
.btn-secondary:hover { background: var(--c-border); text-decoration: none; }
.btn-ghost {
  background: transparent;
  color: var(--c-text-muted);
  border-color: transparent;
}
.btn-ghost:hover { background: var(--c-surface-alt); color: var(--c-text); text-decoration: none; }

.form-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--c-border);
}

/* ===== Saved Recipients ===== */
.saved-recipients {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--c-border);
}
.saved-title {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.saved-empty {
  font-size: 0.875rem;
  color: var(--c-text-light);
}
.saved-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.saved-item {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  padding: 12px;
  background: var(--c-surface-alt);
  border-radius: var(--radius-sm);
  border: 1px solid var(--c-border);
}
.saved-item-info {
  flex: 1;
  min-width: 0;
}
.saved-item-name {
  font-weight: 600;
  font-size: 0.875rem;
}
.saved-item-addr {
  font-size: 0.8125rem;
  color: var(--c-text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.saved-item-actions {
  display: flex;
  gap: 4px;
  flex-shrink: 0;
}
.btn-sm {
  padding: 4px 10px;
  font-size: 0.75rem;
}
.btn-danger {
  color: var(--c-error);
  border-color: transparent;
}
.btn-danger:hover { background: var(--c-error-bg); text-decoration: none; }

/* ===== Preview Panel ===== */
.preview-panel {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: calc(var(--header-height) + 16px);
}
.envelope {
  background: var(--c-surface-alt);
  border: 2px dashed var(--c-border-strong);
  border-radius: var(--radius);
  padding: 32px 24px 40px;
  min-height: 260px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
}
.envelope::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 48px;
  background: linear-gradient(to bottom, var(--c-border) 0%, transparent 100%);
  opacity: 0.3;
  border-radius: var(--radius) var(--radius) 0 0;
}
.envelope-return {
  font-size: 0.8125rem;
  color: var(--c-text-light);
  margin-bottom: 48px;
  position: relative;
  z-index: 1;
}
.return-label {
  font-weight: 600;
  color: var(--c-text-muted);
}
.envelope-recipient {
  font-size: 1.0625rem;
  line-height: 1.5;
  font-weight: 500;
  position: relative;
  z-index: 1;
}
.placeholder-text {
  color: var(--c-text-light);
  font-style: italic;
}
.envelope-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 16px;
}
.copy-confirm {
  font-size: 0.8125rem;
  color: var(--c-success);
  margin-top: 8px;
  min-height: 1.2em;
}

/* ===== Examples Section ===== */
.examples-section {
  padding: 48px 0;
  background: var(--c-surface);
  border-top: 1px solid var(--c-border);
}
.examples-section h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 8px;
}
.examples-section > .container > p {
  color: var(--c-text-muted);
  margin-bottom: 24px;
  max-width: 600px;
}
.examples-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}
.example-card {
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 20px;
}
.example-card h3 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.flag { font-size: 1.25rem; }
.example-card address {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-sm);
  padding: 12px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  margin-bottom: 12px;
  line-height: 1.6;
}
.example-notes {
  font-size: 0.8125rem;
  color: var(--c-text-muted);
  padding-left: 16px;
}
.example-notes li {
  position: relative;
  margin-bottom: 4px;
}
.example-notes li::before {
  content: '•';
  position: absolute;
  left: -14px;
  color: var(--c-accent);
}

/* ===== Mistakes Section ===== */
.mistakes-section {
  padding: 48px 0;
  border-top: 1px solid var(--c-border);
}
.mistakes-section h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 8px;
}
.mistakes-section > .container > p {
  color: var(--c-text-muted);
  margin-bottom: 24px;
  max-width: 600px;
}
.mistakes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 16px;
}
.mistake-card {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-left: 4px solid var(--c-accent);
  border-radius: var(--radius);
  padding: 20px;
}
.mistake-card h3 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 6px;
}
.mistake-card p {
  font-size: 0.875rem;
  color: var(--c-text-muted);
  line-height: 1.5;
}

/* ===== How Section ===== */
.how-section {
  padding: 48px 0;
  background: var(--c-surface);
  border-top: 1px solid var(--c-border);
}
.how-section h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 16px;
}
.steps-list {
  counter-reset: steps;
  margin-bottom: 24px;
}
.steps-list li {
  counter-increment: steps;
  position: relative;
  padding: 12px 0 12px 44px;
  font-size: 0.9375rem;
  border-bottom: 1px solid var(--c-border);
}
.steps-list li:last-child { border-bottom: none; }
.steps-list li::before {
  content: counter(steps);
  position: absolute;
  left: 0;
  top: 10px;
  width: 28px;
  height: 28px;
  background: var(--c-primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
}
.note-box {
  background: var(--c-primary-light);
  border: 1px solid rgba(43,92,230,0.2);
  border-radius: var(--radius);
  padding: 20px;
}
.note-box h3 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--c-primary-hover);
}
.note-box ul {
  font-size: 0.875rem;
  padding-left: 18px;
}
.note-box li {
  position: relative;
  margin-bottom: 4px;
  color: var(--c-text-muted);
}
.note-box li::before {
  content: '✓';
  position: absolute;
  left: -16px;
  color: var(--c-success);
}

/* ===== FAQ Section ===== */
.faq-section {
  padding: 48px 0;
  border-top: 1px solid var(--c-border);
}
.faq-section h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 20px;
}
.faq-list {
  max-width: 720px;
}
.faq-list dt {
  font-weight: 700;
  font-size: 0.9375rem;
  margin-bottom: 6px;
  margin-top: 20px;
}
.faq-list dt:first-child { margin-top: 0; }
.faq-list dd {
  font-size: 0.875rem;
  color: var(--c-text-muted);
  line-height: 1.6;
}

/* ===== Footer ===== */
.site-footer {
  background: var(--c-text);
  color: var(--c-text-light);
  padding: 32px 0 20px;
  margin-top: 32px;
}
.footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 20px;
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 0.875rem;
  color: #fff;
}
.footer-brand svg { color: var(--c-primary); }
.footer-links {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}
.footer-links a {
  padding: 4px 8px;
  font-size: 0.8125rem;
  color: var(--c-text-light);
  border-radius: var(--radius-sm);
  transition: background var(--transition), color var(--transition);
}
.footer-links a:hover {
  background: rgba(255,255,255,0.1);
  color: #fff;
  text-decoration: none;
}
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 16px;
  font-size: 0.8125rem;
}
.footer-bottom p { margin-bottom: 4px; }
.footer-meta { color: rgba(255,255,255,0.4); }

/* ===== Print Styles ===== */
@media print {
  body { background: #fff; }
  .site-header, .site-footer, .form-panel, .envelope-actions, .copy-confirm, .hero, .how-section, .mistakes-section, .examples-section, .faq-section { display: none !important; }
  .formatter-grid { padding: 0; }
  .grid-layout { display: block; }
  .preview-panel { border: none; box-shadow: none; padding: 0; position: static; }
  .envelope { border: none; padding: 40px; min-height: 0; }
  .envelope::before { display: none; }
  .envelope-return { margin-bottom: 60px; }
  .envelope-recipient { font-size: 1.25rem; }
}

/* ===== Responsive ===== */
@media (max-width: 860px) {
  .grid-layout { grid-template-columns: 1fr; }
  .preview-panel { position: static; }
}

@media (max-width: 600px) {
  .main-nav { display: none; }
  .nav-toggle { display: flex; }
  .main-nav.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--c-surface);
    border-bottom: 1px solid var(--c-border);
    padding: 12px 20px;
    box-shadow: var(--shadow);
    z-index: 99;
  }
  .main-nav.open a { padding: 10px 8px; font-size: 0.9375rem; }
  .field-row { grid-template-columns: 1fr; }
  .form-actions { flex-direction: column; }
  .form-actions .btn { width: 100%; }
  .hero { padding: 32px 0 20px; }
}

/* ===== Focus Visible ===== */
:focus-visible {
  outline: 2px solid var(--c-primary);
  outline-offset: 2px;
}

/* ===== Skip Link ===== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 16px;
  background: var(--c-primary);
  color: #fff;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  z-index: 1000;
  font-weight: 600;
}
.skip-link:focus { top: 8px; }



/* Factory-injected deployment helpers. The AI owns the site design above this block. */
.ad-unit {
  width: min(100%, 720px);
  min-height: 120px;
  margin: 24px auto;
  display: block;
}

.legal-page {
  width: min(900px, calc(100% - 32px));
  margin: 40px auto;
}

.factory-fallback-nav {
  width: min(900px, calc(100% - 32px));
  margin: 24px auto 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 16px;
  align-items: center;
  font-size: 0.95rem;
}

.factory-fallback-nav a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid currentColor;
}