/* ============================================================
   QR Studio — Premium Design System
   ============================================================ */

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

:root {
  --color-bg:          #0a0a0f;
  --color-surface:     #111118;
  --color-surface-2:   #16161f;
  --color-surface-3:   #1c1c28;
  --color-border:      rgba(255,255,255,0.07);
  --color-border-hover:rgba(255,255,255,0.14);

  --color-primary:     #6366f1;
  --color-primary-light: #818cf8;
  --color-primary-glow: rgba(99,102,241,0.25);
  --color-accent:      #a78bfa;

  --color-text:        #f1f5f9;
  --color-text-2:      #94a3b8;
  --color-text-3:      #64748b;

  --color-success:     #10b981;
  --color-error:       #f43f5e;

  --radius-sm:  8px;
  --radius-md:  12px;
  --radius-lg:  18px;
  --radius-xl:  24px;

  --shadow-sm:  0 1px 3px rgba(0,0,0,0.4);
  --shadow-md:  0 4px 20px rgba(0,0,0,0.5);
  --shadow-lg:  0 8px 40px rgba(0,0,0,0.6);
  --shadow-glow:0 0 40px rgba(99,102,241,0.15);

  --font:       'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  --transition: 0.2s cubic-bezier(0.4,0,0.2,1);
  --transition-slow: 0.4s cubic-bezier(0.4,0,0.2,1);
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* ---------- Background Decoration ---------- */
.bg-decoration {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.bg-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.45;
  animation: floatOrb 12s ease-in-out infinite;
}

.bg-orb--1 {
  width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(99,102,241,0.3), transparent 70%);
  top: -200px; left: -100px;
  animation-delay: 0s;
}

.bg-orb--2 {
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(167,139,250,0.2), transparent 70%);
  bottom: -150px; right: -100px;
  animation-delay: -4s;
}

.bg-orb--3 {
  width: 300px; height: 300px;
  background: radial-gradient(circle, rgba(16,185,129,0.15), transparent 70%);
  top: 50%; left: 50%;
  transform: translate(-50%,-50%);
  animation-delay: -8s;
}

@keyframes floatOrb {
  0%, 100% { transform: translateY(0) scale(1); }
  33%       { transform: translateY(-30px) scale(1.05); }
  66%       { transform: translateY(20px) scale(0.97); }
}

/* ---------- Layout ---------- */
.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* ---------- Header ---------- */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10,10,15,0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
}

.header__inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header__brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-icon {
  width: 36px; height: 36px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  box-shadow: 0 4px 12px var(--color-primary-glow);
}

.brand-name {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.3px;
  background: linear-gradient(135deg, #fff 40%, var(--color-primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header__badge {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.3px;
  color: var(--color-success);
  background: rgba(16,185,129,0.1);
  border: 1px solid rgba(16,185,129,0.25);
  border-radius: 20px;
  padding: 4px 12px;
}

/* ---------- Main ---------- */
.main {
  padding: 60px 0 80px;
  position: relative;
  z-index: 1;
}

/* ---------- Hero ---------- */
.hero {
  text-align: center;
  margin-bottom: 56px;
}

.hero__tag {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--color-primary-light);
  background: rgba(99,102,241,0.1);
  border: 1px solid rgba(99,102,241,0.2);
  border-radius: 20px;
  padding: 5px 14px;
  margin-bottom: 24px;
}

.tag-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--color-primary-light);
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%       { opacity: 0.5; transform: scale(0.8); }
}

.hero__title {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  font-weight: 800;
  letter-spacing: -1.5px;
  line-height: 1.15;
  margin-bottom: 18px;
  color: var(--color-text);
}

.gradient-text {
  background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-accent) 50%, #f472b6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  font-size: 1.05rem;
  color: var(--color-text-2);
  max-width: 520px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ---------- App Card ---------- */
.app-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
  background: var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  border: 1px solid var(--color-border);
  position: relative;
}

.app-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-xl);
  padding: 1px;
  background: linear-gradient(135deg, rgba(99,102,241,0.3), transparent 50%, rgba(167,139,250,0.2));
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: destination-out;
  mask-composite: exclude;
  pointer-events: none;
}

/* ---------- Panels ---------- */
.panel {
  background: var(--color-surface);
  padding: 32px;
}

.panel--input {
  border-right: 1px solid var(--color-border);
}

.panel--preview {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

/* ---------- Section Label ---------- */
.section-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  color: var(--color-text-3);
  margin-bottom: 14px;
}

/* ---------- Type Grid ---------- */
.type-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin-bottom: 28px;
}

.type-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 5px;
  padding: 11px 6px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-2);
  color: var(--color-text-2);
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font);
  position: relative;
  overflow: hidden;
}

.type-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  opacity: 0;
  transition: var(--transition);
}

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

.type-btn.active {
  border-color: var(--color-primary);
  color: #fff;
  background: var(--color-surface-3);
  box-shadow: 0 0 0 1px var(--color-primary), 0 4px 16px var(--color-primary-glow);
}

.type-btn.active::before {
  opacity: 0.08;
}

.type-btn__icon {
  font-size: 1.2rem;
  position: relative;
  z-index: 1;
}

.type-btn__label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.2px;
  position: relative;
  z-index: 1;
}

/* ---------- Input Forms ---------- */
.input-form {
  display: none;
}

.input-form.active {
  display: block;
}

/* ---------- Fields ---------- */
.field {
  margin-bottom: 16px;
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.field--row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 12px 14px;
}

.field__label {
  display: block;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--color-text-2);
  margin-bottom: 7px;
  letter-spacing: 0.2px;
}

.optional {
  font-weight: 400;
  color: var(--color-text-3);
}

.field__input {
  width: 100%;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 11px 14px;
  color: var(--color-text);
  font-family: var(--font);
  font-size: 0.9rem;
  outline: none;
  transition: var(--transition);
  appearance: none;
  -webkit-appearance: none;
}

.field__input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-glow);
  background: var(--color-surface-3);
}

.field__input::placeholder {
  color: var(--color-text-3);
}

.field__textarea {
  resize: vertical;
  min-height: 90px;
  line-height: 1.6;
}

.field__select {
  cursor: pointer;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}

.field__select option {
  background: var(--color-surface-3);
  color: var(--color-text);
}

/* Password field */
.field__password-wrap {
  position: relative;
}

.field__password-wrap .field__input {
  padding-right: 44px;
}

.password-toggle {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  color: var(--color-text-3);
  cursor: pointer;
  padding: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
  transition: var(--transition);
}

.password-toggle:hover {
  color: var(--color-text-2);
}

/* ---------- Toggle ---------- */
.toggle {
  position: relative;
  display: inline-block;
  width: 42px;
  height: 24px;
  cursor: pointer;
}

.toggle input {
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle__track {
  position: absolute;
  inset: 0;
  background: var(--color-surface-3);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  transition: var(--transition);
}

.toggle__track::after {
  content: '';
  position: absolute;
  left: 3px;
  top: 50%;
  transform: translateY(-50%);
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-text-3);
  transition: var(--transition);
}

.toggle input:checked + .toggle__track {
  background: var(--color-primary);
  border-color: var(--color-primary);
}

.toggle input:checked + .toggle__track::after {
  left: calc(100% - 19px);
  background: #fff;
}

/* ---------- Divider ---------- */
.divider {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 24px 0;
}

.divider::before,
.divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--color-border);
}

.divider span {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.6px;
  text-transform: uppercase;
  color: var(--color-text-3);
}

/* ---------- Customize Grid ---------- */
.customize-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.customize-item {
  /* nothing special needed, uses field styles */
}

/* ---------- Color Swatch ---------- */
.color-swatch-wrap {
  /* wrapper */
}

.color-swatch {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 9px 12px;
  cursor: pointer;
  transition: var(--transition);
}

.color-swatch:hover {
  border-color: var(--color-border-hover);
}

.color-swatch input[type="color"] {
  width: 0;
  height: 0;
  opacity: 0;
  position: absolute;
  pointer-events: none;
}

.color-swatch__preview {
  width: 28px;
  height: 28px;
  border-radius: 6px;
  border: 2px solid rgba(255,255,255,0.15);
  flex-shrink: 0;
  transition: var(--transition);
}

.color-swatch__hex {
  font-size: 0.82rem;
  font-weight: 600;
  font-family: 'Courier New', monospace;
  color: var(--color-text-2);
  letter-spacing: 0.5px;
}

/* ---------- Slider ---------- */
.slider-wrap {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 11px 14px;
}

.slider {
  flex: 1;
  -webkit-appearance: none;
  appearance: none;
  height: 4px;
  border-radius: 2px;
  background: var(--color-surface-3);
  outline: none;
  cursor: pointer;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  cursor: pointer;
  box-shadow: 0 2px 8px var(--color-primary-glow);
  transition: var(--transition);
}

.slider::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

.slider::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  cursor: pointer;
  border: none;
  box-shadow: 0 2px 8px var(--color-primary-glow);
}

.slider-val {
  font-size: 0.78rem;
  font-weight: 700;
  font-family: 'Courier New', monospace;
  color: var(--color-primary-light);
  min-width: 44px;
  text-align: right;
}

/* ---------- Preset Colors ---------- */
.preset-colors {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.preset {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
  outline: none;
}

.preset:hover {
  transform: scale(1.18);
  border-color: rgba(255,255,255,0.4);
}

.preset.selected {
  border-color: #fff;
  box-shadow: 0 0 0 2px var(--color-primary);
}

/* ---------- Generate Button ---------- */
.btn-generate {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 15px 24px;
  border-radius: var(--radius-md);
  border: none;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  color: #fff;
  font-family: var(--font);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.2px;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  box-shadow: 0 4px 20px var(--color-primary-glow), 0 2px 8px rgba(0,0,0,0.3);
}

.btn-generate::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.15), transparent);
  opacity: 0;
  transition: var(--transition);
}

.btn-generate:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px var(--color-primary-glow), 0 4px 16px rgba(0,0,0,0.4);
}

.btn-generate:hover::before {
  opacity: 1;
}

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

/* Shimmer animation on button */
.btn-generate::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -75%;
  width: 50%;
  height: 200%;
  background: linear-gradient(to right, transparent, rgba(255,255,255,0.2), transparent);
  transform: skewX(-20deg);
  animation: shimmer 3s ease-in-out infinite;
}

@keyframes shimmer {
  0%   { left: -75%; }
  60%, 100% { left: 125%; }
}

/* ---------- Preview Panel ---------- */
.preview-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.preview-actions {
  display: flex;
  gap: 8px;
  transition: opacity var(--transition);
}

.icon-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  color: var(--color-text-2);
  font-family: var(--font);
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.icon-btn:hover {
  background: var(--color-surface-3);
  border-color: var(--color-border-hover);
  color: var(--color-text);
}

/* ---------- QR Preview Box ---------- */
.qr-preview-box {
  flex: 1;
  min-height: 260px;
  border-radius: var(--radius-lg);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  transition: var(--transition-slow);
}

/* Subtle checkerboard hint */
.qr-preview-box::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(45deg, rgba(255,255,255,0.015) 25%, transparent 25%),
    linear-gradient(-45deg, rgba(255,255,255,0.015) 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, rgba(255,255,255,0.015) 75%),
    linear-gradient(-45deg, transparent 75%, rgba(255,255,255,0.015) 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0;
  border-radius: var(--radius-lg);
}

.qr-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  text-align: center;
  padding: 32px;
  position: relative;
  z-index: 1;
}

.qr-placeholder__icon {
  color: var(--color-text-3);
  opacity: 0.5;
  margin-bottom: 8px;
}

.qr-placeholder p {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text-3);
}

.qr-placeholder span {
  font-size: 0.8rem;
  color: var(--color-text-3);
  opacity: 0.6;
}

.qr-canvas-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  position: relative;
  z-index: 1;
  animation: fadeInScale 0.35s cubic-bezier(0.34,1.56,0.64,1);
}

@keyframes fadeInScale {
  from { opacity: 0; transform: scale(0.85); }
  to   { opacity: 1; transform: scale(1); }
}

.qr-canvas-wrap canvas {
  border-radius: var(--radius-md);
  box-shadow: 0 8px 32px rgba(0,0,0,0.5);
  max-width: 100%;
  height: auto;
}

/* ---------- Download Section ---------- */
.download-section {
  transition: opacity var(--transition);
}

.download-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  color: var(--color-text-3);
  margin-bottom: 10px;
}

.download-btns {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
}

.btn-download {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 8px;
  border-radius: var(--radius-sm);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  color: var(--color-text-2);
  font-family: var(--font);
  font-size: 0.8rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  letter-spacing: 0.3px;
}

.btn-download:hover {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 4px 16px var(--color-primary-glow);
}

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

/* ---------- QR Info ---------- */
.qr-info {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 12px;
}

.qr-info__item {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.qr-info__label {
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--color-text-3);
}

.qr-info__value {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--color-primary-light);
}

/* ---------- Features Row ---------- */
.features {
  display: grid;
  grid-template-columns: repeat(4,1fr);
  gap: 16px;
  margin-top: 48px;
}

.feature-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
  text-align: center;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  bottom: -40px;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 80px;
  background: radial-gradient(circle, var(--color-primary-glow), transparent);
  opacity: 0;
  transition: var(--transition-slow);
}

.feature-card:hover {
  border-color: var(--color-border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.feature-card:hover::before {
  opacity: 1;
  bottom: -20px;
}

.feature-card__icon {
  font-size: 1.8rem;
  margin-bottom: 12px;
}

.feature-card__title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 6px;
}

.feature-card__desc {
  font-size: 0.78rem;
  color: var(--color-text-3);
  line-height: 1.6;
}

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--color-border);
  padding: 28px 0;
  text-align: center;
  position: relative;
  z-index: 1;
}

.footer p {
  font-size: 0.82rem;
  color: var(--color-text-3);
}

/* ---------- Toast ---------- */
.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--color-surface-3);
  border: 1px solid var(--color-border-hover);
  border-radius: var(--radius-md);
  padding: 12px 20px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease, transform 0.3s ease;
  z-index: 9999;
  white-space: nowrap;
}

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

/* ---------- Loading State ---------- */
.btn-generate.loading {
  pointer-events: none;
}

.btn-generate.loading svg {
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .app-card {
    grid-template-columns: 1fr;
  }

  .panel--input {
    border-right: none;
    border-bottom: 1px solid var(--color-border);
  }

  .features {
    grid-template-columns: repeat(2,1fr);
  }

  .type-grid {
    grid-template-columns: repeat(4,1fr);
  }
}

@media (max-width: 600px) {
  .main {
    padding: 40px 0 60px;
  }

  .hero__title {
    font-size: 2rem;
  }

  .panel {
    padding: 24px 20px;
  }

  .type-grid {
    grid-template-columns: repeat(4,1fr);
  }

  .customize-grid {
    grid-template-columns: 1fr;
  }

  .download-btns {
    grid-template-columns: repeat(3,1fr);
  }

  .features {
    grid-template-columns: 1fr 1fr;
    gap: 12px;
  }

  .field-row {
    grid-template-columns: 1fr;
  }

  .qr-info {
    grid-template-columns: 1fr 1fr 1fr;
  }
}

@media (max-width: 400px) {
  .type-grid {
    grid-template-columns: repeat(4,1fr);
  }

  .type-btn__label {
    font-size: 0.62rem;
  }
}


/* ============================================================
   QR Studio — Extended Content Sections
   ============================================================ */

/* ---------- Header Nav ---------- */
.header__nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

.header__nav a {
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--color-text-3);
  text-decoration: none;
  padding: 5px 11px;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.header__nav a:hover {
  color: var(--color-text);
  background: var(--color-surface-2);
}

/* ---------- Ad Slots ---------- */
/* ---------- Hero Stats ---------- */
.hero__stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  margin-top: 36px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 20px 32px;
  width: fit-content;
  margin-left: auto;
  margin-right: auto;
}

.hero__stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 0 28px;
}

.hero__stat-num {
  font-size: 1.8rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
}

.hero__stat-label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.3px;
  color: var(--color-text-3);
  text-transform: uppercase;
  white-space: nowrap;
}

.hero__stat-div {
  width: 1px;
  height: 40px;
  background: var(--color-border);
  flex-shrink: 0;
}

/* ---------- Content Section Shared ---------- */
.content-section {
  margin-bottom: 24px;
}

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-header__tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  color: var(--color-primary-light);
  background: rgba(99,102,241,0.1);
  border: 1px solid rgba(99,102,241,0.2);
  border-radius: 20px;
  padding: 4px 14px;
  margin-bottom: 16px;
}

.section-header__title {
  font-size: clamp(1.6rem, 3.5vw, 2.2rem);
  font-weight: 800;
  letter-spacing: -0.8px;
  color: var(--color-text);
  margin-bottom: 14px;
  line-height: 1.25;
}

.section-header__sub {
  font-size: 1rem;
  color: var(--color-text-2);
  max-width: 580px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ---------- How-to Steps ---------- */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.step-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px 22px;
  position: relative;
  overflow: hidden;
  transition: var(--transition);
}

.step-card::after {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  opacity: 0;
  transition: var(--transition);
}

.step-card:hover {
  border-color: var(--color-border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.step-card:hover::after {
  opacity: 1;
}

.step-card__num {
  font-size: 3rem;
  font-weight: 800;
  color: rgba(99,102,241,0.1);
  line-height: 1;
  margin-bottom: 12px;
  font-variant-numeric: tabular-nums;
}

.step-card__icon {
  font-size: 1.6rem;
  margin-bottom: 14px;
}

.step-card__title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 10px;
}

.step-card__desc {
  font-size: 0.82rem;
  color: var(--color-text-2);
  line-height: 1.7;
}

/* ---------- QR Types Grid ---------- */
.types-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.type-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 26px;
  transition: var(--transition);
}

.type-card:hover {
  border-color: var(--color-border-hover);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.type-card__header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}

.type-card__icon {
  font-size: 1.5rem;
  width: 44px;
  height: 44px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.type-card__title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-text);
}

.type-card__desc {
  font-size: 0.83rem;
  color: var(--color-text-2);
  line-height: 1.75;
  margin-bottom: 14px;
}

.type-card__desc code {
  font-family: 'Courier New', monospace;
  font-size: 0.78rem;
  background: var(--color-surface-3);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 1px 6px;
  color: var(--color-primary-light);
}

.type-card__use {
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--color-success);
  background: rgba(16,185,129,0.08);
  border: 1px solid rgba(16,185,129,0.2);
  border-radius: var(--radius-sm);
  padding: 5px 12px;
  display: inline-block;
}

/* ---------- Use Cases Grid ---------- */
.usecase-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.usecase-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.usecase-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at top left, rgba(99,102,241,0.06), transparent 60%);
  opacity: 0;
  transition: var(--transition-slow);
}

.usecase-card:hover {
  border-color: var(--color-border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.usecase-card:hover::before {
  opacity: 1;
}

.usecase-card__icon {
  font-size: 1.8rem;
  margin-bottom: 14px;
  display: block;
}

.usecase-card__title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 10px;
}

.usecase-card p {
  font-size: 0.8rem;
  color: var(--color-text-2);
  line-height: 1.7;
  position: relative;
  z-index: 1;
}

/* ---------- Tips Grid ---------- */
.tips-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.tip-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 22px 20px;
  transition: var(--transition);
}

.tip-card:hover {
  border-color: rgba(99,102,241,0.3);
  box-shadow: 0 0 0 1px rgba(99,102,241,0.1), var(--shadow-md);
  transform: translateY(-2px);
}

.tip-card__icon {
  font-size: 1.5rem;
  margin-bottom: 12px;
  display: block;
}

.tip-card__title {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 10px;
}

.tip-card__text {
  font-size: 0.8rem;
  color: var(--color-text-2);
  line-height: 1.75;
}

/* ---------- FAQ Accordion ---------- */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition);
}

.faq-item.open {
  border-color: rgba(99,102,241,0.35);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 22px;
  background: none;
  border: none;
  color: var(--color-text);
  font-family: var(--font);
  font-size: 0.92rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  transition: var(--transition);
}

.faq-question:hover {
  color: var(--color-primary-light);
}

.faq-icon {
  font-size: 1.3rem;
  font-weight: 300;
  color: var(--color-text-3);
  flex-shrink: 0;
  transition: transform var(--transition), color var(--transition);
  line-height: 1;
}

.faq-item.open .faq-icon {
  transform: rotate(45deg);
  color: var(--color-primary-light);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s cubic-bezier(0.4,0,0.2,1),
              padding 0.35s cubic-bezier(0.4,0,0.2,1);
}

.faq-answer p {
  padding: 0 22px 20px;
  font-size: 0.87rem;
  color: var(--color-text-2);
  line-height: 1.8;
}

.faq-answer p strong {
  color: var(--color-text);
  font-weight: 600;
}

.faq-item.open .faq-answer {
  max-height: 600px;
}

/* ---------- About Section ---------- */
.about-section {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
}

.about-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 48px;
  padding: 48px;
  align-items: center;
}

.about-text h2 {
  font-size: 1.6rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: var(--color-text);
  margin-bottom: 18px;
}

.about-text p {
  font-size: 0.87rem;
  color: var(--color-text-2);
  line-height: 1.8;
  margin-bottom: 14px;
}

.about-text p:last-child {
  margin-bottom: 0;
}

.about-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  min-width: 240px;
}

.about-stat {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 20px;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.about-stat__num {
  font-size: 2rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
}

.about-stat__label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.3px;
  text-transform: uppercase;
  color: var(--color-text-3);
}

/* ---------- Footer Extended ---------- */
.footer__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  text-align: center;
}

.footer__brand {
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer__copy {
  font-size: 0.8rem;
  color: var(--color-text-3);
  max-width: 480px;
  line-height: 1.6;
}

.footer__links {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-wrap: wrap;
  justify-content: center;
}

.footer__links a {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--color-text-3);
  text-decoration: none;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.footer__links a:hover {
  color: var(--color-text);
  background: var(--color-surface-2);
}

/* ---------- Responsive: Extended Sections ---------- */
@media (max-width: 1100px) {
  .tips-grid     { grid-template-columns: repeat(2, 1fr); }
  .usecase-grid  { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 900px) {
  .steps-grid    { grid-template-columns: repeat(2, 1fr); }
  .types-grid    { grid-template-columns: 1fr; }
  .about-inner   { grid-template-columns: 1fr; gap: 32px; padding: 32px 24px; }
  .about-stats   { grid-template-columns: repeat(4, 1fr); min-width: unset; }

  .hero__stats {
    padding: 16px 20px;
    gap: 0;
  }

  .hero__stat {
    padding: 0 16px;
  }
}

@media (max-width: 700px) {
  .steps-grid    { grid-template-columns: 1fr; }
  .usecase-grid  { grid-template-columns: 1fr 1fr; }
  .tips-grid     { grid-template-columns: 1fr 1fr; }
  .about-stats   { grid-template-columns: repeat(2, 1fr); }

  .hero__stats {
    flex-wrap: wrap;
    gap: 16px;
    width: 100%;
    justify-content: center;
    padding: 20px;
  }

  .hero__stat-div {
    display: none;
  }

  .hero__stat {
    padding: 0 12px;
  }

  .section-header__title {
    font-size: 1.5rem;
  }

  .faq-question {
    font-size: 0.85rem;
    padding: 15px 16px;
  }

  .faq-answer p {
    padding: 0 16px 16px;
  }
}

@media (max-width: 500px) {
  .usecase-grid  { grid-template-columns: 1fr; }
  .tips-grid     { grid-template-columns: 1fr; }
  .about-stats   { grid-template-columns: repeat(2, 1fr); }
  .header__nav   { display: none; }
}