/* =========================================================
   QRForge — Root Stylesheet
   Serves ONLY: homepage (index.html), /qr/ generator pages,
   and static pages (faq · about · terms · privacy)
   ========================================================= */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

/* ---------- Design tokens ---------- */
:root {
  --bg: #fafafa;
  --surface: #ffffff;
  --surface-2: #f4f4f5;
  --text: #09090b;
  --text-muted: #71717a;
  --border: #e4e4e7;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-subtle: #eff6ff;
  --danger: #dc2626;
  --danger-bg: #fef2f2;
  --success: #16a34a;
  --success-bg: #f0fdf4;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 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 / 0.05);
  --shadow-lg: 0 10px 30px -10px rgb(0 0 0 / 0.12);
  --header-h: 64px;
  --font: "Inter", ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}

html.dark {
  --bg: #09090b;
  --surface: #18181b;
  --surface-2: #27272a;
  --text: #fafafa;
  --text-muted: #a1a1aa;
  --border: #27272a;
  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --accent-subtle: #172554;
  --danger: #ef4444;
  --danger-bg: #450a0a;
  --success: #22c55e;
  --success-bg: #052e16;
  --shadow: 0 1px 2px 0 rgb(0 0 0 / 0.4);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4), 0 2px 4px -2px rgb(0 0 0 / 0.3);
  --shadow-lg: 0 10px 30px -10px rgb(0 0 0 / 0.5);
}

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

html { font-size: 16px; -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4 { font-weight: 700; letter-spacing: -0.025em; color: var(--text); }
h1 { font-size: 2.25rem; line-height: 1.2; }
h2 { font-size: 1.5rem; line-height: 1.3; }
h3 { font-size: 1.125rem; line-height: 1.4; }
p { color: var(--text-muted); }

a { color: var(--accent); text-decoration: none; transition: color 0.15s ease; }
a:hover { color: var(--accent-hover); }

/* Layout */
.container { width: 100%; max-width: 1120px; margin: 0 auto; padding: 0 1.25rem; }
.container-wide { max-width: 1280px; }

/* ---------- Header (glassy sticky) ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: color-mix(in srgb, var(--surface) 86%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 1.25rem;
}
.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 800;
  font-size: 1.125rem;
  color: var(--text);
  letter-spacing: -0.03em;
}
.logo span { color: var(--accent); }
.logo:hover { color: var(--text); }

.nav { display: flex; align-items: center; gap: 0.2rem; }
.nav a {
  padding: 0.42rem 0.85rem;
  border-radius: 999px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.15s, background 0.15s;
}
.nav a:hover {
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 8%, transparent);
}
.nav a.active {
  background: var(--accent);
  color: #fff;
  font-weight: 600;
}

.header-actions { display: flex; align-items: center; gap: 0.5rem; }

/* Theme toggle */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-muted);
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.theme-toggle:hover { background: var(--surface-2); color: var(--text); border-color: var(--accent); }
.theme-toggle svg {
  width: 18px;
  height: 18px;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.75;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.theme-toggle .icon-sun { display: none; }
html.dark .theme-toggle .icon-moon { display: none; }
html.dark .theme-toggle .icon-sun { display: block; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  padding: 0.6rem 1.15rem;
  font-size: 0.875rem;
  font-weight: 600;
  font-family: inherit;
  border-radius: 10px;
  border: 1px solid transparent;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.15s, border-color 0.15s, color 0.15s, box-shadow 0.2s, transform 0.15s;
}
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
  box-shadow: 0 1px 2px color-mix(in srgb, var(--accent) 35%, transparent);
}
.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 16px color-mix(in srgb, var(--accent) 30%, transparent);
}
.btn-primary:active { transform: translateY(0); }

.btn-secondary { background: var(--surface); color: var(--text); border-color: var(--border); }
.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 5%, var(--surface));
}

.btn-ghost { background: transparent; color: var(--text-muted); border-color: transparent; }
.btn-ghost:hover { background: var(--surface-2); color: var(--text); }

.btn-block { width: 100%; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }

/* ---------- Cards ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ---------- Forms ---------- */
.form-group { margin-bottom: 1.25rem; }
label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text);
  margin-bottom: 0.35rem;
}
.hint { font-size: 0.75rem; color: var(--text-muted); margin-top: 0.3rem; }

input[type="text"],
input[type="url"],
input[type="number"],
input[type="color"],
select,
textarea {
  width: 100%;
  padding: 0.6rem 0.8rem;
  font-size: 0.875rem;
  font-family: inherit;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: border-color 0.15s, box-shadow 0.15s;
}
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-subtle);
}
input[type="color"] { padding: 0.25rem; height: 40px; cursor: pointer; }
select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2371717a' stroke-width='2'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  padding-right: 2rem;
}
.input-row { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; }

/* ---------- Alerts ---------- */
.alert {
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.8125rem;
  margin-bottom: 1rem;
  display: none;
}
.alert.show { display: block; }
.alert-error { background: var(--danger-bg); color: var(--danger); border: 1px solid var(--danger); }
.alert-success { background: var(--success-bg); color: var(--success); border: 1px solid var(--success); }

/* ---------- Advanced block ---------- */
.advanced { border: 1px solid var(--border); border-radius: var(--radius); margin-top: 1.5rem; overflow: hidden; }
.advanced-toggle {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.85rem 1rem;
  background: var(--surface-2);
  border: none;
  cursor: pointer;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text);
  font-family: inherit;
}
.advanced-toggle:hover { background: var(--border); }
.advanced-body { padding: 1.25rem; display: none; border-top: 1px solid var(--border); }
.advanced.open .advanced-body { display: block; }
.advanced-toggle svg { width: 16px; height: 16px; transition: transform 0.2s; }
.advanced.open .advanced-toggle svg { transform: rotate(180deg); }

.color-row { display: flex; align-items: center; gap: 0.75rem; }
.color-row input[type="color"] { width: 48px; flex-shrink: 0; }

/* ---------- Workbench (QR generator pages) ---------- */
.workbench {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 1.5rem;
  align-items: start;
  padding: 2rem 0 4rem;
}
.config-panel { min-width: 0; }
.preview-panel { position: sticky; top: calc(var(--header-h) + 1.5rem); }
.preview-card { padding: 1.5rem; text-align: center; }
.preview-viewport {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 240px;
  background: var(--surface-2);
  border-radius: 10px;
  border: 1px dashed var(--border);
  margin-bottom: 1.25rem;
  padding: 1.5rem;
}
.preview-viewport svg, .preview-viewport canvas, .preview-viewport img { max-width: 100%; height: auto; }
.preview-actions { display: flex; flex-direction: column; gap: 0.5rem; }
.preview-actions .btn-row { display: grid; grid-template-columns: 1fr 1fr; gap: 0.5rem; }

/* ---------- Page header & steps ---------- */
.page-header { padding: 1.75rem 0 0.5rem; }
.page-header h1 { font-size: 1.6rem; }
.page-header p { margin-top: 0.25rem; font-size: 0.9375rem; }

.step-indicator {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  font-size: 0.8125rem;
  color: var(--text-muted);
}
.step-indicator .active { color: var(--accent); font-weight: 600; }
.step-indicator .sep { opacity: 0.4; }

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; margin: 3rem 0; }
.step {
  text-align: center;
  padding: 1.5rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: var(--accent);
  color: #fff;
  font-size: 0.875rem;
  font-weight: 700;
  border-radius: 50%;
  margin-bottom: 0.75rem;
}
.step h3 { font-size: 1rem; margin-bottom: 0.35rem; }
.step p { font-size: 0.8125rem; }

/* ---------- QR type picker grid ---------- */
.type-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 0.75rem;
  margin: 1.5rem 0 3rem;
}
.type-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 1.25rem 0.75rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text);
  font-size: 0.8125rem;
  font-weight: 500;
  transition: border-color 0.15s, box-shadow 0.15s, background 0.15s, transform 0.15s;
  text-align: center;
}
.type-card:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
  background: var(--accent-subtle);
  color: var(--text);
  transform: translateY(-2px);
}
.type-card .type-icon {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--surface-2);
  border-radius: var(--radius-sm);
  font-size: 1.25rem;
}

/* ---------- Accordion (faq/about pages) ---------- */
.accordion { max-width: 720px; margin: 0 auto 4rem; }
.accordion-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 0.5rem;
  overflow: hidden;
  background: var(--surface);
}
.accordion-trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text);
  text-align: left;
  font-family: inherit;
}
.accordion-trigger:hover { background: var(--surface-2); }
.accordion-trigger svg { width: 18px; height: 18px; flex-shrink: 0; transition: transform 0.2s; color: var(--text-muted); }
.accordion-item.open .accordion-trigger svg { transform: rotate(180deg); }
.accordion-content {
  display: none;
  padding: 0 1.25rem 1.25rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
}
.accordion-item.open .accordion-content { display: block; }

/* ---------- Info block ---------- */
.info-block {
  margin-top: 2.5rem;
  padding: 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.info-block h3 { margin-bottom: 0.75rem; font-size: 1rem; }
.info-block p { font-size: 0.875rem; margin-bottom: 0.5rem; }
.info-block p:last-child { margin-bottom: 0; }

/* ---------- Utilities ---------- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}
.hidden { display: none !important; }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .workbench { grid-template-columns: 1fr; }
  .preview-panel { position: static !important; }
}
@media (max-width: 640px) {
  .input-row { grid-template-columns: 1fr; }
  .nav { display: none; }
  .steps { grid-template-columns: 1fr; }
  .type-grid { grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); }
}