/* ============================================================
   static/style.css  –  MLF PDF Splitter  (Premium Dark UI)
   ============================================================ */

/* ── Google Fonts ─────────────────────────────────────────── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

/* ── CSS Custom Properties ────────────────────────────────── */
:root {
  /* Colour palette */
  --bg-base:        #0b0f1a;
  --bg-card:        #111827;
  --bg-card-hover:  #161e30;
  --bg-surface:     #1c2537;
  --bg-input:       #1a2133;

  --accent-primary: #4f8ef7;
  --accent-glow:    rgba(79, 142, 247, 0.35);
  --accent-success: #22c55e;
  --accent-warn:    #f59e0b;
  --accent-error:   #ef4444;
  --accent-error-bg:#3b0f0f;

  --text-primary:   #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted:     #475569;
  --border:         rgba(255,255,255,0.08);
  --border-focus:   rgba(79,142,247,0.6);

  /* Spacing / radius */
  --radius-sm:  8px;
  --radius-md:  14px;
  --radius-lg:  20px;
  --radius-xl:  28px;

  /* Animation */
  --ease-out:   cubic-bezier(0.22, 1, 0.36, 1);
  --transition: 0.25s var(--ease-out);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background-color: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  padding: 2rem 1rem 4rem;

  /* Subtle animated gradient background */
  background-image:
    radial-gradient(ellipse 80% 60% at 50% -10%, rgba(79,142,247,0.12) 0%, transparent 70%),
    radial-gradient(ellipse 60% 40% at 90% 80%,  rgba(99,70,240,0.08) 0%, transparent 60%);
}

/* ── Page Header ──────────────────────────────────────────── */
.page-header {
  text-align: center;
  margin-bottom: 2.5rem;
  animation: fadeDown 0.6s var(--ease-out) both;
}

.page-header .logo-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
}

.page-header .logo-icon {
  width: 46px;
  height: 46px;
  background: linear-gradient(135deg, #4f8ef7, #7c60f5);
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-size: 1.4rem;
  box-shadow: 0 0 24px rgba(79,142,247,0.4);
}

.page-header h1 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, #e2e8f0 30%, #4f8ef7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.page-header p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-top: 0.35rem;
}

/* ── Main Card ────────────────────────────────────────────── */
.card {
  width: 100%;
  max-width: 620px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 2.2rem 2.4rem;
  box-shadow: 0 24px 64px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.03);
  animation: fadeUp 0.65s var(--ease-out) 0.1s both;
}

/* ── Drop Zone ────────────────────────────────────────────── */
.drop-zone {
  border: 2px dashed rgba(79,142,247,0.3);
  border-radius: var(--radius-lg);
  padding: 2.8rem 1.5rem;
  text-align: center;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition), transform var(--transition);
  position: relative;
  overflow: hidden;
  background: rgba(79,142,247,0.03);
}

.drop-zone::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 50%, rgba(79,142,247,0.08) 0%, transparent 70%);
  opacity: 0;
  transition: opacity var(--transition);
}

.drop-zone:hover::before,
.drop-zone.drag-over::before { opacity: 1; }

.drop-zone:hover,
.drop-zone.drag-over {
  border-color: var(--accent-primary);
  background: rgba(79,142,247,0.06);
  transform: scale(1.005);
}

.drop-zone.has-file {
  border-color: var(--accent-success);
  border-style: solid;
  background: rgba(34,197,94,0.05);
}

.drop-zone .dz-icon {
  font-size: 2.6rem;
  margin-bottom: 0.8rem;
  display: block;
  transition: transform var(--transition);
}

.drop-zone:hover .dz-icon { transform: translateY(-4px); }

.drop-zone h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.3rem;
}

.drop-zone p {
  font-size: 0.825rem;
  color: var(--text-secondary);
}

.drop-zone .browse-link {
  color: var(--accent-primary);
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* Hidden real input */
#fileInput { display: none; }

/* File selected pill */
.file-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 1rem;
  padding: 0.45rem 0.9rem;
  background: rgba(34,197,94,0.15);
  border: 1px solid rgba(34,197,94,0.3);
  border-radius: 999px;
  font-size: 0.8rem;
  color: var(--accent-success);
  font-weight: 500;
  max-width: 100%;
  overflow: hidden;
}

.file-pill span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; max-width: 300px; }

.file-pill .remove-btn {
  background: none;
  border: none;
  color: var(--accent-success);
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
  opacity: 0.7;
  transition: opacity var(--transition);
  flex-shrink: 0;
}

.file-pill .remove-btn:hover { opacity: 1; }

/* ── Form Fields ──────────────────────────────────────────── */
.fields-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 1.4rem;
}

.field-group {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.field-group label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.field-group input[type="number"] {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.7rem 1rem;
  font-size: 0.95rem;
  font-family: inherit;
  color: var(--text-primary);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
  width: 100%;
  -moz-appearance: textfield;
}

.field-group input[type="number"]::-webkit-inner-spin-button,
.field-group input[type="number"]::-webkit-outer-spin-button { -webkit-appearance: none; }

.field-group input[type="number"]:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.field-group input[type="number"].invalid {
  border-color: var(--accent-error);
  box-shadow: 0 0 0 3px rgba(239,68,68,0.2);
}

.field-error {
  font-size: 0.75rem;
  color: var(--accent-error);
  min-height: 1em;
}

/* ── Submit Button ────────────────────────────────────────── */
.btn-submit {
  width: 100%;
  margin-top: 1.6rem;
  padding: 0.85rem 1.5rem;
  border: none;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #4f8ef7, #6952f5);
  color: #fff;
  font-size: 1rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: opacity var(--transition), transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 4px 20px rgba(79,142,247,0.35);
  letter-spacing: 0.01em;
}

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

.btn-submit:hover:not(:disabled)::before { opacity: 1; }

.btn-submit:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(79,142,247,0.5);
}

.btn-submit:active:not(:disabled) { transform: translateY(0); }

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

/* ── Loading State ────────────────────────────────────────── */
.loading-section {
  display: none;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  margin-top: 1.8rem;
  padding: 1.4rem;
  background: var(--bg-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  animation: fadeUp 0.4s var(--ease-out) both;
}

.loading-section.visible { display: flex; }

.spinner {
  width: 44px;
  height: 44px;
  border: 3px solid rgba(79,142,247,0.2);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 0.9s linear infinite;
}

.loading-section p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  text-align: center;
}

.loading-section .processing-dots::after {
  content: '';
  animation: dots 1.4s infinite;
}

/* ── Result Section ───────────────────────────────────────── */
.result-section {
  display: none;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1.8rem;
  animation: fadeUp 0.5s var(--ease-out) both;
}

.result-section.visible { display: flex; }

/* Success banner */
.success-banner {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 1rem 1.2rem;
  background: rgba(34,197,94,0.1);
  border: 1px solid rgba(34,197,94,0.25);
  border-radius: var(--radius-md);
}

.success-banner .banner-icon { font-size: 1.6rem; flex-shrink: 0; }

.success-banner h4 {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--accent-success);
  margin-bottom: 0.15rem;
}

.success-banner p {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* Download button */
.btn-download {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 0.85rem 1.5rem;
  border: none;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #1aac5a, #059669);
  color: #fff;
  font-size: 1rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 4px 20px rgba(34,197,94,0.3);
  text-decoration: none;
}

.btn-download:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(34,197,94,0.45);
}

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

/* Block summary list */
.block-summary {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.block-summary-header {
  padding: 0.7rem 1rem;
  background: rgba(255,255,255,0.03);
  border-bottom: 1px solid var(--border);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.block-list {
  list-style: none;
  max-height: 240px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--bg-surface) transparent;
}

.block-list::-webkit-scrollbar { width: 5px; }
.block-list::-webkit-scrollbar-thumb { background: var(--bg-surface); border-radius: 999px; }

.block-item {
  display: flex;
  align-items: flex-start;
  gap: 0.8rem;
  padding: 0.7rem 1rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.82rem;
  transition: background var(--transition);
}

.block-item:last-child { border-bottom: none; }
.block-item:hover { background: rgba(255,255,255,0.02); }

.block-item .bi-index {
  width: 22px;
  height: 22px;
  background: rgba(79,142,247,0.15);
  border-radius: 6px;
  display: grid;
  place-items: center;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--accent-primary);
  flex-shrink: 0;
}

.block-item .bi-name {
  font-weight: 600;
  color: var(--text-primary);
  word-break: break-all;
}

.block-item .bi-meta {
  color: var(--text-muted);
  margin-top: 0.2rem;
}

/* ── Error Banner ─────────────────────────────────────────── */
.error-banner {
  display: none;
  align-items: flex-start;
  gap: 0.85rem;
  padding: 1rem 1.2rem;
  background: var(--accent-error-bg);
  border: 1px solid rgba(239,68,68,0.35);
  border-radius: var(--radius-md);
  margin-top: 1.4rem;
  animation: shake 0.4s var(--ease-out);
}

.error-banner.visible { display: flex; }

.error-banner .err-icon { font-size: 1.3rem; flex-shrink: 0; margin-top: 0.1rem; }

.error-banner h4 {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--accent-error);
  margin-bottom: 0.2rem;
}

.error-banner p {
  font-size: 0.8rem;
  color: #fca5a5;
}

/* ── Reset link ───────────────────────────────────────────── */
.reset-row {
  text-align: center;
  margin-top: 0.6rem;
}

.btn-reset {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 0.8rem;
  cursor: pointer;
  transition: color var(--transition);
  font-family: inherit;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.btn-reset:hover { color: var(--text-secondary); }

/* ── Footer ───────────────────────────────────────────────── */
.page-footer {
  margin-top: 2.5rem;
  text-align: center;
  animation: fadeUp 0.7s var(--ease-out) 0.2s both;
}

.page-footer .footer-brand {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  background: linear-gradient(135deg, #4f8ef7, #a78bfa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 0.25rem;
}

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

/* ── Total Pages Badge ────────────────────────────────────── */
.total-pages-row {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  margin-top: 0.9rem;
  padding: 0.55rem 1rem;
  background: rgba(79,142,247,0.08);
  border: 1px solid rgba(79,142,247,0.2);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: var(--text-secondary);
  animation: fadeUp 0.3s var(--ease-out) both;
}

.total-pages-row .tp-icon { font-size: 1rem; }

.total-pages-row strong {
  color: var(--accent-primary);
  font-weight: 700;
}

/* Tiny inline spinners */
.meta-spinner,
.preview-spinner {
  display: inline-block;
  width: 14px;
  height: 14px;
  border: 2px solid rgba(79,142,247,0.25);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  vertical-align: middle;
}

/* ── Preview Section ──────────────────────────────────────── */
.preview-section {
  margin-top: 1.2rem;
  border: 1px solid rgba(79,142,247,0.2);
  border-radius: var(--radius-md);
  background: rgba(79,142,247,0.04);
  overflow: hidden;
  animation: fadeUp 0.35s var(--ease-out) both;
}

.preview-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1rem;
  background: rgba(79,142,247,0.08);
  border-bottom: 1px solid rgba(79,142,247,0.15);
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--accent-primary);
  text-transform: uppercase;
  letter-spacing: 0.07em;
}

.preview-content {
  padding: 0.75rem 1rem;
  max-height: 260px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--bg-surface) transparent;
}

.preview-content::-webkit-scrollbar { width: 5px; }
.preview-content::-webkit-scrollbar-thumb { background: var(--bg-surface); border-radius: 999px; }

.preview-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
  padding: 0.5rem 0;
}

.preview-error {
  font-size: 0.8rem;
  color: var(--accent-error);
  padding: 0.3rem 0;
}

.preview-count {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--accent-primary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 0.6rem;
}

.preview-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.preview-item {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  padding: 0.55rem 0.7rem;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  transition: background var(--transition);
}

.preview-item:hover { background: var(--bg-card-hover); }

.pv-index {
  width: 20px;
  height: 20px;
  background: rgba(79,142,247,0.18);
  border-radius: 5px;
  display: grid;
  place-items: center;
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--accent-primary);
  flex-shrink: 0;
}

.pv-body { flex: 1; min-width: 0; }

.pv-pages {
  color: var(--text-secondary);
  margin-bottom: 0.2rem;
  word-break: break-all;
}

.pv-pages strong { color: var(--text-primary); }

.pv-trains {
  color: var(--text-muted);
  font-size: 0.75rem;
  word-break: break-all;
}

/* ── Animations ───────────────────────────────────────────── */
@keyframes fadeDown {
  from { opacity: 0; transform: translateY(-18px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(18px); }
  to   { opacity: 1; transform: translateY(0); }
}

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

@keyframes dots {
  0%   { content: ''; }
  33%  { content: '.'; }
  66%  { content: '..'; }
  100% { content: '...'; }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%       { transform: translateX(-6px); }
  40%       { transform: translateX(6px); }
  60%       { transform: translateX(-4px); }
  80%       { transform: translateX(4px); }
}

/* ── Responsive ───────────────────────────────────────────── */
@media (max-width: 480px) {
  .card { padding: 1.5rem 1.2rem; }
  .fields-row { grid-template-columns: 1fr; }
}

/* ── Welcome Toast ────────────────────────────────────────── */
.welcome-toast {
  position: fixed;
  bottom: 1.8rem;
  right: 1.8rem;
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.75rem 1.25rem;
  background: linear-gradient(135deg, #1e2d50, #0f172a);
  border: 1px solid rgba(79,142,247,0.35);
  border-radius: var(--radius-md);
  box-shadow: 0 8px 32px rgba(0,0,0,0.55), 0 0 0 1px rgba(79,142,247,0.1);
  color: var(--text-primary);
  font-size: 0.88rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  z-index: 9999;

  /* Hidden by default – slides up when .toast-visible is added */
  opacity: 0;
  transform: translateY(24px);
  pointer-events: none;
  transition: opacity 0.4s var(--ease-out), transform 0.4s var(--ease-out);
}

.welcome-toast.toast-visible {
  opacity: 1;
  transform: translateY(0);
}

.welcome-toast .toast-icon {
  font-size: 1.15rem;
  flex-shrink: 0;
}

.welcome-toast .toast-msg {
  background: linear-gradient(135deg, #e2e8f0, #4f8ef7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}