/* ==========================================================================
   RupeeShift Design System & Styling
   ========================================================================== */

:root {
  /* Dark Theme Tokens (Default) */
  --bg-primary: #0b0f19;
  --bg-secondary: #111827;
  --bg-card: rgba(17, 24, 39, 0.75);
  --bg-panel: rgba(31, 41, 55, 0.6);
  --bg-panel-hover: rgba(55, 65, 81, 0.5);
  --bg-panel-focus: rgba(31, 41, 55, 0.95);
  --bg-chip: rgba(55, 65, 81, 0.5);
  --bg-chip-hover: #4f46e5;
  
  --border-color: rgba(75, 85, 99, 0.35);
  --border-focus: #6366f1;
  --border-subtle: rgba(255, 255, 255, 0.08);

  --text-primary: #f9fafb;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;
  --text-accent: #818cf8;

  --accent-primary: #6366f1;
  --accent-primary-hover: #4f46e5;
  --accent-glow: rgba(99, 102, 241, 0.25);

  --success: #10b981;
  --success-glow: rgba(16, 185, 129, 0.2);
  --warning: #f59e0b;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 25px var(--accent-glow);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

/* Light Theme Tokens */
[data-theme="light"] {
  --bg-primary: #f3f4f6;
  --bg-secondary: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.9);
  --bg-panel: rgba(243, 244, 246, 0.8);
  --bg-panel-hover: rgba(229, 231, 235, 0.8);
  --bg-panel-focus: #ffffff;
  --bg-chip: #e5e7eb;
  --bg-chip-hover: #4f46e5;

  --border-color: rgba(209, 213, 219, 0.8);
  --border-focus: #4f46e5;
  --border-subtle: rgba(0, 0, 0, 0.06);

  --text-primary: #111827;
  --text-secondary: #4b5563;
  --text-muted: #6b7280;
  --text-accent: #4f46e5;

  --accent-primary: #4f46e5;
  --accent-primary-hover: #4338ca;
  --accent-glow: rgba(79, 70, 229, 0.15);

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
  --shadow-glow: 0 0 20px rgba(79, 70, 229, 0.12);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 24px 16px;
  background-image: 
    radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.12) 0%, transparent 40%),
    radial-gradient(circle at 90% 80%, rgba(16, 185, 129, 0.08) 0%, transparent 40%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
}

.app-container {
  width: 100%;
  max-width: 640px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 4px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-flags {
  display: flex;
  align-items: center;
  gap: 4px;
  background: var(--bg-secondary);
  padding: 6px 10px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.flag-icon {
  font-size: 1.35rem;
  line-height: 1;
}

.flag-divider {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 600;
}

.brand-text h1 {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  background: linear-gradient(135deg, var(--text-primary) 40%, var(--text-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand-text .tagline {
  font-size: 0.78rem;
  color: var(--text-secondary);
  font-weight: 500;
}

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

.rate-status-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 5px 10px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  box-shadow: var(--shadow-sm);
  white-space: nowrap;
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background-color: var(--success);
  box-shadow: 0 0 8px var(--success);
}

.status-dot.warning {
  background-color: var(--warning);
  box-shadow: 0 0 8px var(--warning);
}

.icon-btn {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  cursor: pointer;
  width: 38px;
  height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.icon-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-focus);
  background: var(--bg-panel-hover);
}

.icon {
  width: 18px;
  height: 18px;
}

/* Theme Icons Toggle */
[data-theme="dark"] .icon-sun {
  display: block;
}
[data-theme="dark"] .icon-moon {
  display: none;
}
[data-theme="light"] .icon-sun {
  display: none;
}
[data-theme="light"] .icon-moon {
  display: block;
}

.spin {
  animation: spin 0.8s ease-in-out;
}

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

/* ==========================================================================
   Main Converter Card
   ========================================================================== */

.converter-card {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 24px;
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  gap: 16px;
  position: relative;
  overflow: hidden;
}

/* Currency Panel */
.currency-panel {
  background: var(--bg-panel);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 16px 18px;
  transition: var(--transition);
}

.currency-panel:focus-within {
  background: var(--bg-panel-focus);
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

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

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

.currency-flag {
  font-size: 1.5rem;
  line-height: 1;
}

.currency-info {
  display: flex;
  flex-direction: column;
}

.currency-code {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--text-primary);
}

.currency-name {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.text-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.text-btn:hover {
  color: var(--text-primary);
  background: var(--bg-chip);
}

.copy-icon {
  width: 14px;
  height: 14px;
}

/* Input Area */
.input-container {
  display: flex;
  align-items: center;
  gap: 8px;
}

.symbol-prefix {
  font-size: 1.6rem;
  font-weight: 600;
  color: var(--text-muted);
  user-select: none;
}

.input-container input {
  width: 100%;
  background: transparent;
  border: none;
  outline: none;
  font-family: var(--font-mono);
  font-size: 2.1rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.input-container input::placeholder {
  color: var(--text-muted);
  opacity: 0.5;
}

.panel-footer {
  margin-top: 6px;
}

.amount-in-words {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-style: italic;
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Swap Divider */
.swap-divider {
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  gap: 12px;
  margin: -4px 0;
}

.divider-line {
  flex: 1;
  height: 1px;
  background: var(--border-color);
}

.swap-button {
  background: var(--accent-primary);
  color: #ffffff;
  border: 3px solid var(--bg-card);
  border-radius: var(--radius-full);
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-md), var(--shadow-glow);
  transition: var(--transition);
  z-index: 2;
}

.swap-button:hover {
  background: var(--accent-primary-hover);
  transform: scale(1.08) rotate(180deg);
}

.swap-button:active {
  transform: scale(0.95) rotate(180deg);
}

.swap-icon {
  width: 20px;
  height: 20px;
}

.rate-summary-badge {
  position: absolute;
  right: 0;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--bg-panel);
  padding: 4px 10px;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-color);
  font-family: var(--font-mono);
}

@media (max-width: 480px) {
  .rate-summary-badge {
    display: none;
  }
}

/* Preset Chips */
.presets-section {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-top: 4px;
}

.presets-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.presets-title {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.presets-hint {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.preset-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.preset-chip {
  background: var(--bg-chip);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition);
  user-select: none;
}

.preset-chip:hover {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
  transform: translateY(-1px);
}

.preset-chip:active {
  transform: translateY(0);
}

/* Advanced Settings Accordion */
.advanced-section {
  border-top: 1px solid var(--border-color);
  padding-top: 14px;
}

.advanced-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  list-style: none;
  user-select: none;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: var(--transition);
}

.advanced-summary::-webkit-details-marker {
  display: none;
}

.advanced-summary:hover {
  color: var(--text-primary);
}

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

.summary-icon {
  width: 16px;
  height: 16px;
  color: var(--text-muted);
}

.chevron-icon {
  width: 16px;
  height: 16px;
  transition: transform 0.2s ease;
}

details[open] .chevron-icon {
  transform: rotate(180deg);
}

.advanced-body {
  margin-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: 14px;
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

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

.setting-label-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.setting-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-primary);
}

.reset-rate-btn {
  font-size: 0.75rem;
  color: var(--accent-primary);
}

.custom-rate-control {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
}

.custom-rate-control input {
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 600;
  width: 100%;
}

.custom-rate-prefix,
.custom-rate-suffix {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.setting-hint {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.fee-percentage-badge {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--accent-primary);
  background: var(--accent-glow);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
}

.fee-slider-container {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent-primary);
  cursor: pointer;
}

.slider-marks {
  display: flex;
  justify-content: space-between;
  font-size: 0.68rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Quick Reference Cheat Sheet
   ========================================================================== */

.cheatsheet-section {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.section-header h2 {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text-primary);
}

.section-desc {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.table-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

@media (max-width: 580px) {
  .table-grid {
    grid-template-columns: 1fr;
  }
}

.cheatsheet-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 14px;
  box-shadow: var(--shadow-sm);
}

.cheatsheet-card-title {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text-secondary);
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 10px;
}

.cheatsheet-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
}

.cheatsheet-table th {
  text-align: left;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding-bottom: 6px;
}

.cheatsheet-table td {
  padding: 6px 0;
  border-bottom: 1px solid var(--border-subtle);
  font-family: var(--font-mono);
  color: var(--text-primary);
}

.cheatsheet-table tr:last-child td {
  border-bottom: none;
}

.text-right {
  text-align: right;
}

/* ==========================================================================
   Travel & Payment Insights
   ========================================================================== */

.tips-section {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.tips-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
}

.tip-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px;
  display: flex;
  gap: 10px;
  align-items: flex-start;
  box-shadow: var(--shadow-sm);
}

.tip-icon {
  font-size: 1.4rem;
  line-height: 1;
}

.tip-content h3 {
  font-size: 0.82rem;
  font-weight: 700;
  margin-bottom: 4px;
  color: var(--text-primary);
}

.tip-content p {
  font-size: 0.74rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* ==========================================================================
   Footer
   ========================================================================== */

.app-footer {
  text-align: center;
  padding: 16px 0 24px;
  border-top: 1px solid var(--border-subtle);
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.footer-content p {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.footer-badges {
  display: flex;
  gap: 6px;
}

.badge {
  font-size: 0.68rem;
  font-weight: 600;
  padding: 2px 8px;
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
}

/* ==========================================================================
   Toast Notification
   ========================================================================== */

.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: #111827;
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.2);
  padding: 10px 18px;
  border-radius: var(--radius-full);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.4);
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.82rem;
  font-weight: 600;
  opacity: 0;
  pointer-events: none;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  z-index: 100;
}

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

.toast-icon {
  background: var(--success);
  color: #ffffff;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
}