/* ============================================
   PayQR — Mobile-First Premium Dark Theme
   UPI QR Code Generator PWA
   ============================================ */

/* ---- CSS Custom Properties ---- */
:root {
  --bg: #0a0a0f;
  --surface: #141420;
  --surface-hover: #1a1a2e;
  --border: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(0, 184, 107, 0.4);
  --text-primary: #f0f0f5;
  --text-secondary: #8888a0;
  --accent: #00B86B;
  --accent-hover: #00d67e;
  --accent-glow: rgba(0, 184, 107, 0.2);
  --accent-glow-strong: rgba(0, 184, 107, 0.35);
  --whatsapp: #25D366;
  --whatsapp-hover: #2be675;
  --error: #ff4757;
  --error-bg: rgba(255, 71, 87, 0.1);
  --radius: 14px;
  --radius-lg: 20px;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
}

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

/* ---- Base ---- */
html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.5;
  color: var(--text-primary);
  background-color: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overscroll-behavior: none;
  min-height: 100dvh;
}

::selection {
  background-color: var(--accent);
  color: #fff;
}

/* ---- App Layout ---- */
.app-container {
  max-width: 480px;
  margin: 0 auto;
  padding: 16px 20px;
  padding-bottom: calc(20px + env(safe-area-inset-bottom, 0px));
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

/* ---- Header ---- */
.app-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 0 24px;
}

.app-logo {
  flex-shrink: 0;
}

.app-title {
  font-size: 1.35rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent), #4aeaaa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.02em;
}

/* ---- Form Section ---- */
.form-section {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.input-label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
  transition: color 0.2s ease;
}

.input-group:focus-within .input-label {
  color: var(--accent);
}

.label-optional {
  font-weight: 400;
  text-transform: none;
  letter-spacing: 0;
  opacity: 0.6;
}

.input-field {
  height: 52px;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  padding: 0 16px;
  color: var(--text-primary);
  font-size: 1rem;
  font-family: var(--font);
  font-weight: 500;
  transition: all 0.2s ease;
  width: 100%;
  -webkit-appearance: none;
  appearance: none;
}

.input-field::placeholder {
  color: var(--text-secondary);
  opacity: 0.5;
}

.input-field:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
  background: var(--surface-hover);
}

/* Amount input with ₹ prefix */
.input-with-prefix {
  position: relative;
}

.input-prefix {
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  font-size: 1.1rem;
  font-weight: 600;
  pointer-events: none;
  z-index: 1;
}

.input-field--amount {
  padding-left: 38px;
}

/* Remove number input spinners */
.input-field--amount::-webkit-outer-spin-button,
.input-field--amount::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}
.input-field--amount[type=number] {
  -moz-appearance: textfield;
}

.input-hint {
  font-size: 0.72rem;
  color: var(--text-secondary);
  opacity: 0.7;
}

/* Validation error styles */
.input-error {
  font-size: 0.75rem;
  color: var(--error);
  min-height: 0;
  overflow: hidden;
  transition: all 0.2s ease;
  display: none;
}

.input-group.error .input-field {
  border-color: var(--error);
  box-shadow: 0 0 0 3px var(--error-bg);
}

.input-group.error .input-error {
  display: block;
}

.input-group.error .input-label {
  color: var(--error);
}

/* ---- Save Profile Checkbox ---- */
.save-profile {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  padding: 4px 0;
}

.save-profile input[type="checkbox"] {
  display: none;
}

.checkbox-custom {
  width: 22px;
  height: 22px;
  border: 2px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  flex-shrink: 0;
  position: relative;
}

.checkbox-custom::after {
  content: '';
  width: 12px;
  height: 12px;
  border-radius: 3px;
  background: var(--accent);
  transform: scale(0);
  transition: transform 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.save-profile input:checked + .checkbox-custom {
  border-color: var(--accent);
}

.save-profile input:checked + .checkbox-custom::after {
  transform: scale(1);
}

.save-profile-text {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* ---- Buttons ---- */
.btn-generate {
  width: 100%;
  height: 56px;
  background: var(--accent);
  color: #fff;
  font-family: var(--font);
  font-weight: 600;
  font-size: 1.05rem;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  transition: all 0.2s ease;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  user-select: none;
  box-shadow: 0 4px 20px var(--accent-glow);
  margin-top: 6px;
}

.btn-generate:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 28px var(--accent-glow-strong);
}

.btn-generate:active {
  transform: translateY(0) scale(0.97);
}

.btn-generate.loading {
  opacity: 0.7;
  pointer-events: none;
}

.btn-generate.success {
  background: #0d9e5c;
}

.btn-icon {
  flex-shrink: 0;
}

/* Action Buttons Group */
.btn-group {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 20px;
}

.btn-whatsapp {
  width: 100%;
  height: 52px;
  background: var(--whatsapp);
  color: #fff;
  font-family: var(--font);
  font-weight: 600;
  font-size: 1rem;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  transition: all 0.2s ease;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  user-select: none;
  box-shadow: 0 4px 16px rgba(37, 211, 102, 0.25);
}

.btn-whatsapp:hover {
  background: var(--whatsapp-hover);
  transform: translateY(-1px);
}

.btn-whatsapp:active {
  transform: translateY(0) scale(0.97);
}

.btn-download {
  width: 100%;
  height: 52px;
  background: transparent;
  color: var(--text-primary);
  font-family: var(--font);
  font-weight: 500;
  font-size: 1rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  transition: all 0.2s ease;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  user-select: none;
}

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

.btn-download:active {
  transform: scale(0.97);
}

.btn-download.success {
  border-color: var(--accent);
  color: var(--accent);
}

/* ---- QR Display Section ---- */
.qr-section {
  opacity: 0;
  max-height: 0;
  overflow: hidden;
  transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  margin-top: 0;
}

.qr-section.visible {
  opacity: 1;
  max-height: 2000px;
  margin-top: 28px;
  overflow: visible;
}

.qr-card {
  text-align: center;
}

.qr-container {
  background: #ffffff;
  border-radius: var(--radius-lg);
  padding: 24px 20px;
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  box-shadow: 0 0 40px rgba(255, 255, 255, 0.08);
  margin: 0 auto;
  max-width: 320px;
}

.qr-header {
  text-align: center;
  width: 100%;
}

.qr-name-label {
  font-size: 1.1rem;
  font-weight: 700;
  color: #1a1a2e;
  letter-spacing: 0.01em;
  margin: 0 0 2px 0;
  text-align: center;
}

.qr-upi-label {
  font-size: 0.82rem;
  font-weight: 500;
  color: #6b6b80;
  text-align: center;
  margin: 0;
  letter-spacing: 0.02em;
}

.qr-divider {
  width: 100%;
  height: 1.5px;
  background: #e8e8ee;
  margin: 2px 0;
}

.qr-inner {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 4px 0;
}

.qr-instructions {
  width: 100%;
  text-align: left;
}

.qr-inst-title {
  font-size: 0.88rem;
  font-weight: 700;
  color: #1a1a2e;
  margin: 0 0 10px 0;
  text-align: center;
}

.qr-inst-step {
  font-size: 0.8rem;
  color: #444456;
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 6px 0;
  line-height: 1.35;
}

.qr-inst-step strong {
  color: #1a1a2e;
}

.qr-step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: #00B86B;
  color: #fff;
  font-size: 0.7rem;
  font-weight: 700;
  flex-shrink: 0;
}

.qr-subdivider {
  height: 1px;
  background: #f0f0f5;
  margin: 10px 0;
}

.qr-inst-wa {
  font-size: 0.76rem;
  color: #555568;
  line-height: 1.45;
  margin: 0;
  text-align: center;
}

.qr-inst-wa strong {
  color: #00965e;
}

.qr-section.visible .qr-container {
  animation: fadeInUp 0.4s ease-out;
}

.qr-container canvas {
  border-radius: 8px;
}

.qr-amount-text {
  font-size: 1.6rem;
  font-weight: 700;
  margin-top: 18px;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.qr-payee-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* ---- Footer ---- */
.app-footer {
  margin-top: auto;
  padding: 24px 0 8px;
  text-align: center;
  font-size: 0.7rem;
  color: var(--text-secondary);
  opacity: 0.5;
  line-height: 1.7;
}

/* ---- Animations ---- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.02); }
}

/* Form entry animation */
.main-content {
  animation: fadeInUp 0.5s ease-out;
}

/* ---- Responsive ---- */
@media (min-width: 640px) {
  .app-container {
    padding: 24px 32px;
  }

  .input-field {
    height: 54px;
  }

  .btn-generate {
    height: 58px;
  }

  .btn-group {
    flex-direction: row;
  }

  .btn-whatsapp,
  .btn-download {
    flex: 1;
  }
}

/* ---- Landscape phone fix ---- */
@media (max-height: 500px) and (orientation: landscape) {
  .app-container {
    min-height: auto;
  }
}

/* ---- Accessibility ---- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* ---- Print ---- */
@media print {
  body {
    background: #fff;
    color: #000;
  }

  .form-section,
  .btn-group,
  .save-profile,
  .app-footer,
  .btn-generate {
    display: none !important;
  }

  .qr-section {
    opacity: 1 !important;
    max-height: none !important;
    overflow: visible !important;
  }

  .qr-container {
    box-shadow: none;
    border: 1px solid #ccc;
  }

  .qr-amount-text,
  .qr-payee-text {
    color: #000;
  }
}