:root {
  --bg-app: #f8fafc;
  --bg-card: #ffffff;
  --bg-header: #ffffff;
  --bg-subtle: #f1f5f9;

  --border: #e2e8f0;
  --border-hover: #cbd5e1;
  --border-focus: #3b82f6;

  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-shadow: rgba(37, 99, 235, 0.28);

  --text-main: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;

  --radius-card: 12px;
  --radius-btn: 8px;
  --radius-sm: 6px;

  --font-sans: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --shadow-card: 0 1px 3px 0 rgba(15, 23, 42, 0.04), 0 4px 12px 0 rgba(15, 23, 42, 0.03);
  --shadow-card-hover: 0 4px 6px -1px rgba(15, 23, 42, 0.05), 0 16px 28px -4px rgba(15, 23, 42, 0.08);
  --shadow-btn: 0 2px 4px 0 rgba(37, 99, 235, 0.2);
  --shadow-btn-hover: 0 4px 14px 0 rgba(37, 99, 235, 0.35);

  --transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html, body {
  height: 100vh;
  width: 100vw;
  overflow: hidden;
  background-color: var(--bg-app);
  color: var(--text-main);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
}

.app-layout {
  height: 100vh;
  width: 100vw;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-in {
  animation: fadeInUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.delay-1 {
  animation-delay: 0.08s;
}

.delay-2 {
  animation-delay: 0.16s;
}

.navbar {
  height: 56px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  padding: 0 1.75rem;
  background: var(--bg-header);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 1px 2px 0 rgba(15, 23, 42, 0.03);
  z-index: 10;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.brand-icon {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  background-color: var(--primary);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 6px rgba(37, 99, 235, 0.25);
}

.brand-title {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--text-main);
}

.workspace-grid {
  flex: 1;
  min-height: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
  padding: 1.25rem 1.75rem 1.5rem;
  overflow: hidden;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: var(--transition);
}

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

.card-header {
  height: 48px;
  flex-shrink: 0;
  padding: 0 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
  background: #fafbfd;
}

.card-header h2 {
  font-size: 0.925rem;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.01em;
}

.card-form {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  clip: rect(0, 0, 0, 0);
  overflow: hidden;
}

textarea {
  flex: 1;
  min-height: 0;
  width: 100%;
  padding: 1.25rem;
  background: #ffffff;
  border: none;
  resize: none;
  font-family: inherit;
  font-size: 0.95rem;
  color: var(--text-main);
  line-height: 1.65;
  outline: none;
  overflow-y: auto;
}

textarea::placeholder {
  color: #94a3b8;
}

textarea::-webkit-scrollbar,
.card-body::-webkit-scrollbar {
  width: 6px;
}

textarea::-webkit-scrollbar-thumb,
.card-body::-webkit-scrollbar-thumb {
  background: #cbd5e1;
  border-radius: var(--radius-sm);
}

textarea::-webkit-scrollbar-thumb:hover,
.card-body::-webkit-scrollbar-thumb:hover {
  background: #94a3b8;
}

textarea.shake {
  animation: shake 0.35s ease-in-out;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-5px); }
  75% { transform: translateX(5px); }
}

.card-footer {
  height: 54px;
  flex-shrink: 0;
  padding: 0 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border);
  background: #fafbfd;
}

.char-count {
  font-size: 0.8125rem;
  color: var(--text-muted);
  font-weight: 500;
}

.btn-primary {
  background: var(--primary);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-btn);
  padding: 0.5rem 1.15rem;
  font-family: inherit;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  box-shadow: var(--shadow-btn);
  transition: var(--transition);
}

.btn-primary:hover:not(:disabled) {
  background: var(--primary-hover);
  box-shadow: var(--shadow-btn-hover);
  transform: translateY(-1px);
}

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

.btn-primary:disabled {
  opacity: 0.6;
  cursor: wait;
}

.btn-outline {
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  font-family: inherit;
  font-size: 0.8125rem;
  font-weight: 600;
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-btn);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  cursor: pointer;
  transition: var(--transition);
}

.btn-outline:hover:not(:disabled) {
  background: var(--bg-subtle);
  border-color: var(--border-hover);
  color: var(--text-main);
  transform: translateY(-1px);
}

.btn-outline:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-outline.copied {
  background: #ecfdf5;
  border-color: #a7f3d0;
  color: #059669;
}

.btn-ghost {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-family: inherit;
  font-size: 0.8125rem;
  font-weight: 500;
  padding: 0.3rem 0.6rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
}

.btn-ghost:hover {
  color: #dc2626;
  background: #fee2e2;
}

.spinner {
  display: none;
  width: 14px;
  height: 14px;
  border: 2px solid rgba(255, 255, 255, 0.4);
  border-top-color: #ffffff;
  border-radius: 50%;
  animation: spin 0.65s linear infinite;
}

.btn-primary.loading .spinner {
  display: inline-block;
}

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

.card-body {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  background: #ffffff;
}

.summary-box {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-left: 3.5px solid var(--primary);
  border-radius: var(--radius-btn);
  padding: 1.25rem 1.5rem;
  font-size: 1rem;
  line-height: 1.75;
  color: var(--text-main);
  animation: popIn 0.25s ease-out;
}

@keyframes popIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.empty-state {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  text-align: center;
  font-size: 0.9rem;
}

.skeleton-loader {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  width: 100%;
}

.skeleton-line {
  height: 14px;
  border-radius: 4px;
  background: linear-gradient(90deg, #f1f5f9 25%, #e2e8f0 50%, #f1f5f9 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

.skeleton-line:nth-child(1) { width: 88%; }
.skeleton-line:nth-child(2) { width: 96%; }
.skeleton-line:nth-child(3) { width: 72%; }

@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

@media (max-width: 820px) {
  html, body {
    height: auto;
    overflow-y: auto;
  }
  .app-layout {
    height: auto;
    overflow: visible;
  }
  .workspace-grid {
    grid-template-columns: 1fr;
    height: auto;
    overflow: visible;
    gap: 1.25rem;
    padding: 1rem;
  }
  .card {
    height: 400px;
  }
}