@layer base, layout, components;

@layer base {
  *, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }

  :root {
    --color-bg: oklch(97% 0.008 255);
    --color-surface: oklch(100% 0 0);
    --color-surface-alt: oklch(98.5% 0.005 255);
    --color-border: oklch(90% 0.01 255);
    --color-text: oklch(22% 0.025 255);
    --color-text-muted: oklch(52% 0.015 255);

    --color-primary: oklch(50% 0.22 258);
    --color-primary-hover: oklch(45% 0.24 258);
    --color-primary-glow: oklch(50% 0.22 258 / 0.28);

    --shadow-sm: 0 1px 3px oklch(0% 0 0 / 0.07), 0 1px 2px oklch(0% 0 0 / 0.04);
    --shadow-md: 0 4px 16px oklch(0% 0 0 / 0.08), 0 2px 4px oklch(0% 0 0 / 0.05);
    --shadow-lg: 0 8px 32px oklch(0% 0 0 / 0.12), 0 4px 8px oklch(0% 0 0 / 0.07);

    --radius-sm: 7px;
    --radius-md: 12px;
    --radius-lg: 18px;
  }

  html {
    font-size: 16px;
    color-scheme: light;
    -webkit-text-size-adjust: 100%;
  }

  body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
  }

  input, select, button, textarea { font-family: inherit; font-size: inherit; }
  button { cursor: pointer; border: none; background: none; }
  input::placeholder { color: var(--color-text-muted); opacity: 0.7; }
}

@layer layout {
  .noise {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    opacity: 0.025;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='300' height='300' filter='url(%23n)'/%3E%3C/svg%3E");
    background-size: 300px 300px;
  }

  header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: oklch(100% 0 0 / 0.88);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
  }

  .header-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0.875rem 1.5rem;
    display: flex;
    align-items: center;
  }

  main {
    max-width: 1100px;
    margin: 0 auto;
    padding: 2.5rem 1.5rem 4rem;
    position: relative;
    z-index: 1;
  }

  .converter-grid {
    display: grid;
    grid-template-columns: 480px 1fr;
    gap: 1.5rem;
    align-items: start;
  }

  @media (max-width: 960px) {
    .converter-grid { grid-template-columns: 1fr; }
  }

  @media (max-width: 520px) {
    main { padding: 1.25rem 1rem 3rem; }
    .header-inner { padding: 0.75rem 1rem; }
  }
}

@layer components {
  /* ── Brand ─────────────────────────────────────────────── */
  .brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
  }

  .brand-icon { font-size: 1.75rem; line-height: 1; }

  .brand-name {
    display: block;
    font-size: 1.125rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.2;
  }

  .brand-tagline {
    display: block;
    font-size: 0.75rem;
    color: var(--color-text-muted);
    line-height: 1;
  }

  /* ── Card ───────────────────────────────────────────────── */
  .card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
  }

  .card-title {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9375rem;
    font-weight: 600;
    margin-bottom: 1.25rem;
  }

  .card-title svg { color: var(--color-primary); flex-shrink: 0; }

  /* ── Form ───────────────────────────────────────────────── */
  .form-group { margin-bottom: 0.875rem; }

  .form-group label {
    display: block;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--color-text-muted);
    margin-bottom: 0.3rem;
  }

  input[type="text"],
  input[type="number"],
  input[type="date"],
  select {
    width: 100%;
    padding: 0.6rem 0.875rem;
    background: var(--color-surface-alt);
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    font-size: 0.9375rem;
    transition: border-color 0.15s, box-shadow 0.15s;
    appearance: none;
    -webkit-appearance: none;
    outline: none;
  }

  input[type="text"]:focus,
  input[type="number"]:focus,
  input[type="date"]:focus,
  select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow);
  }

  .form-error {
    font-size: 0.8125rem;
    color: oklch(55% 0.23 27);
    min-height: 1.2em;
    margin-bottom: 0.5rem;
  }

  /* ── Buttons ────────────────────────────────────────────── */
  .btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.375rem;
    padding: 0.6rem 1.1rem;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    transition: background-color 0.15s, box-shadow 0.15s, transform 0.1s;
    white-space: nowrap;
    line-height: 1;
  }

  .btn:active { transform: scale(0.965); }

  .btn-primary {
    background: var(--color-primary);
    color: white;
    box-shadow: 0 2px 10px var(--color-primary-glow);
  }

  .btn-primary:hover {
    background: var(--color-primary-hover);
    box-shadow: 0 4px 18px var(--color-primary-glow);
  }

  .btn-primary:disabled {
    opacity: 0.45;
    cursor: not-allowed;
    box-shadow: none;
    transform: none;
  }

  .btn-block { width: 100%; margin-top: 0.25rem; }

  /* ── Converter card ─────────────────────────────────────── */
  .converter-card { position: relative; overflow: hidden; }

  .converter-desc {
    font-size: 0.875rem;
    color: var(--color-text-muted);
    margin-bottom: 1.5rem;
    line-height: 1.6;
  }

  /* ── Upload area ────────────────────────────────────────── */
  .upload-area {
    border: 2px dashed var(--color-border);
    border-radius: var(--radius-md);
    padding: 2.5rem 1.5rem;
    text-align: center;
    cursor: pointer;
    transition: border-color 0.15s, background-color 0.15s;
    margin-bottom: 0.875rem;
    outline: none;
  }

  .upload-area:hover,
  .upload-area:focus-visible {
    border-color: var(--color-primary);
    background: oklch(96% 0.03 258);
  }

  .upload-area.drag-over {
    border-color: var(--color-primary);
    background: oklch(94% 0.05 258);
    transform: scale(1.01);
  }

  .upload-area input[type="file"] { display: none; }

  .upload-emoji { font-size: 2.5rem; display: block; margin-bottom: 0.625rem; }

  .upload-main {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-text);
    margin-bottom: 0.375rem;
    line-height: 1.5;
  }

  .upload-hint { font-size: 0.8rem; color: var(--color-text-muted); }

  /* ── File chip ──────────────────────────────────────────── */
  .file-chip {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.75rem;
    background: oklch(95% 0.05 258);
    border: 1px solid oklch(85% 0.08 258);
    border-radius: var(--radius-sm);
    color: var(--color-primary);
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 0.875rem;
  }

  .file-chip span {
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .file-chip button {
    flex-shrink: 0;
    padding: 2px;
    color: var(--color-primary);
    border-radius: 3px;
    opacity: 0.6;
    transition: opacity 0.15s;
  }

  .file-chip button:hover { opacity: 1; }

  /* ── Form section ───────────────────────────────────────── */
  .form-section {
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 0.75rem 0.875rem 0.25rem;
    margin-bottom: 0.875rem;
    background: var(--color-surface-alt);
  }

  .form-section-header {
    font-size: 0.775rem;
    font-weight: 600;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.625rem;
  }

  .form-row-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
  }

  .form-section .form-group { margin-bottom: 0.625rem; }

  /* ── Route group ────────────────────────────────────────── */
  .route-group {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: end;
    gap: 0.5rem;
    margin-bottom: 0.875rem;
  }

  .route-group .form-group { margin-bottom: 0; }

  .route-arrow {
    padding-bottom: 0.55rem;
    color: var(--color-text-muted);
    display: flex;
    align-items: center;
  }

  /* ── Convert result ─────────────────────────────────────── */
  .convert-result {
    margin-top: 1rem;
    padding: 0.875rem 1rem;
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    font-weight: 500;
  }

  .convert-result.success {
    background: oklch(95% 0.06 145);
    border: 1px solid oklch(80% 0.1 145);
    color: oklch(35% 0.12 145);
  }

  .convert-result.error {
    background: oklch(96% 0.05 27);
    border: 1px solid oklch(80% 0.1 27);
    color: oklch(40% 0.14 27);
  }

  /* ── Loading overlay ────────────────────────────────────── */
  .convert-loading {
    position: absolute;
    inset: 0;
    background: oklch(100% 0 0 / 0.85);
    border-radius: var(--radius-lg);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    backdrop-filter: blur(4px);
    z-index: 10;
  }

  .convert-loading p {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-text-muted);
  }

  .spinner {
    width: 36px;
    height: 36px;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.75s linear infinite;
  }

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

  /* ── Info card ──────────────────────────────────────────── */
  .info-subheading {
    font-size: 0.8125rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text-muted);
    margin-bottom: 0.75rem;
    margin-top: 1.5rem;
  }

  .info-card .info-subheading:first-of-type { margin-top: 0; }

  .info-list {
    padding-left: 1.2rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    font-size: 0.9rem;
    line-height: 1.6;
  }

  .feature-list { list-style: none; padding-left: 0; }

  .feature-list li::before {
    content: "✓";
    color: var(--color-primary);
    font-weight: 700;
    margin-right: 0.5rem;
  }

  .feature-note {
    display: block;
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-top: 0.1rem;
    padding-left: 1.35rem;
  }

  /* ── Toast ──────────────────────────────────────────────── */
  .toast {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    z-index: 500;
    padding: 0.75rem 1.25rem;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.2s ease;
    background: var(--color-text);
    color: white;
    max-width: 320px;
  }

  .toast.hidden { display: none; }

  @keyframes slideUp {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: translateY(0); }
  }

  /* ── Fare DB section ───────────────────────────────────── */
  .fare-db-section {
    background: var(--color-surface-alt);
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 0.875rem 1rem;
    margin-bottom: 1.5rem;
  }

  .fare-db-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.375rem;
  }

  .fare-db-title {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-text);
  }

  .fare-count-badge {
    font-size: 0.7rem;
    font-weight: 600;
    padding: 0.15rem 0.5rem;
    border-radius: 999px;
    background: oklch(50% 0.22 258 / 0.12);
    color: var(--color-primary);
  }

  .fare-db-desc {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-bottom: 0.75rem;
    line-height: 1.5;
  }

  .fare-upload-row {
    display: flex;
    align-items: center;
    gap: 0.625rem;
  }

  .fare-password-input {
    width: 7rem;
    padding: 0.38rem 0.625rem;
    font-size: 0.8125rem;
    background: var(--color-surface);
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    outline: none;
    transition: border-color 0.15s, box-shadow 0.15s;
  }

  .fare-password-input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow);
  }

  .btn-secondary {
    background: var(--color-surface);
    color: var(--color-primary);
    border: 1.5px solid oklch(80% 0.1 258);
  }

  .btn-secondary:hover {
    background: oklch(96% 0.03 258);
    border-color: var(--color-primary);
  }

  .btn-sm {
    font-size: 0.8125rem;
    padding: 0.4rem 0.75rem;
  }

  .fare-upload-status {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    flex: 1;
  }

  .fare-upload-status.ok  { color: oklch(40% 0.14 145); }
  .fare-upload-status.err { color: oklch(50% 0.2 27); }

  /* ── Utility ────────────────────────────────────────────── */
  .hidden { display: none !important; }
}