:root {
  --bg: #f5f7fa;
  --bg-soft: #e5e7eb;
  --card: #ffffff;
  --text: #1f2937;
  --subtext: #6b7280;
  --border: #e5e7eb;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --danger: #ef4444;
  --shadow-soft: 0 18px 45px rgba(15, 23, 42, 0.12);
}

body.dark {
  --bg: #0f172a;
  --bg-soft: #020617;
  --card: #020617;
  --text: #e5e7eb;
  --subtext: #9ca3af;
  --border: #1f2937;
  --primary: #3b82f6;
  --primary-hover: #60a5fa;
  --shadow-soft: 0 18px 45px rgba(0, 0, 0, 0.7);
}

* {
  box-sizing: border-box;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text", sans-serif;
}

body {
  margin: 0;
  background: radial-gradient(circle at top, #e5edff 0, var(--bg) 45%);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 24px 12px;
  transition: background 0.3s ease, color 0.3s ease;
}

.shell {
  width: 100%;
  max-width: 1120px;
  display: flex;
  gap: 16px;
  position: relative;
}

/* Sidebar */

.sidebar-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.45);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
  z-index: 20;
}

.sidebar-backdrop.visible {
  opacity: 1;
  pointer-events: auto;
}

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  height: 100vh;
  width: 260px;
  background: var(--card);
  border-right: 1px solid var(--border);
  box-shadow: 0 18px 45px rgba(15, 23, 42, 0.35);
  transform: translateX(-100%);
  transition: transform 0.25s ease;
  z-index: 30;
  display: flex;
  flex-direction: column;
  padding: 16px 14px;
}

.sidebar.open {
  transform: translateX(0);
}

.sidebar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.sidebar-title {
  font-size: 1rem;
  font-weight: 600;
}

.sidebar-close {
  border: none;
  background: transparent;
  color: var(--subtext);
  cursor: pointer;
  font-size: 1.1rem;
}

.sidebar-list {
  flex: 1;
  overflow-y: auto;
  margin-top: 8px;
  padding-right: 4px;
}

.history-item {
  padding: 8px 10px;
  border-radius: 8px;
  margin-bottom: 6px;
  background: transparent;
  border: 1px solid transparent;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.9rem;
  color: var(--text);
}

.history-item:hover {
  background: var(--bg-soft);
  border-color: var(--border);
}

.history-title {
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  padding-right: 6px;
}

.history-menu-btn {
  border: none;
  background: transparent;
  color: var(--subtext);
  cursor: pointer;
  font-size: 1rem;
  padding: 0 4px;
}

.sidebar-footer {
  margin-top: 10px;
  border-top: 1px solid var(--border);
  padding-top: 10px;
  display: flex;
  justify-content: space-between;
  gap: 8px;
}

.btn-small {
  font-size: 0.8rem;
  padding: 6px 10px;
  border-radius: 999px;
  border: none;
  cursor: pointer;
}

.btn-outline {
  background: transparent;
  color: var(--subtext);
  border: 1px solid var(--border);
}

.btn-outline-danger {
  background: transparent;
  color: var(--danger);
  border: 1px solid rgba(239, 68, 68, 0.4);
}

/* Main app */

.app {
  flex: 1;
  background: var(--card);
  border-radius: 18px;
  padding: 22px 22px 20px;
  box-shadow: var(--shadow-soft);
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.left-header {
  display: flex;
  align-items: center;
  gap: 10px;
}

.sidebar-toggle {
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  padding: 6px 10px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.85rem;
}

.app-title {
  font-size: 1.4rem;
  font-weight: 700;
}

.app-subtitle {
  font-size: 0.85rem;
  color: var(--subtext);
}

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

.toggle-dark {
  cursor: pointer;
  padding: 7px 12px;
  border-radius: 999px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  font-size: 0.85rem;
}

/* Mode + length controls */

.mode-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  justify-content: space-between;
}

.segmented {
  display: inline-flex;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg);
  padding: 3px;
}

.segmented button {
  border: none;
  background: transparent;
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 0.85rem;
  cursor: pointer;
  color: var(--subtext);
}

.segmented button.active {
  background: var(--card);
  color: var(--text);
  box-shadow: 0 0 0 1px var(--border);
}

.mode-label {
  font-size: 0.8rem;
  color: var(--subtext);
}

/* Input area */

.input-card {
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--bg);
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.input-label-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 8px;
}

.input-label {
  font-size: 0.9rem;
  font-weight: 500;
}

.input-hint {
  font-size: 0.8rem;
  color: var(--subtext);
}

textarea {
  width: 100%;
  min-height: 130px;
  resize: vertical;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  font-size: 0.95rem;
}

textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 1px rgba(37, 99, 235, 0.25);
}

/* Tone + length row */

.options-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  justify-content: space-between;
  margin-top: 4px;
}

.select-group {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

select {
  padding: 7px 10px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  font-size: 0.85rem;
}

.btn-primary {
  background: var(--primary);
  color: white;
  border-radius: 999px;
  border: none;
  padding: 8px 16px;
  font-size: 0.9rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-secondary {
  background: var(--bg);
  color: var(--text);
  border-radius: 999px;
  border: 1px solid var(--border);
  padding: 8px 14px;
  font-size: 0.85rem;
  cursor: pointer;
}

/* Loading */

.loading {
  text-align: center;
  margin-top: 10px;
  font-size: 0.9rem;
  color: var(--subtext);
}

.spinner {
  width: 26px;
  height: 26px;
  border: 3px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  margin: 0 auto 8px;
}

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

/* Output */

.output-section {
  margin-top: 6px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.output-header-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
}

.output-title {
  font-size: 0.95rem;
  font-weight: 500;
}

.output-subtitle {
  font-size: 0.8rem;
  color: var(--subtext);
}

.output-card {
  border: 1px solid var(--border);
  padding: 14px 12px 12px;
  border-radius: 12px;
  background: var(--bg);
  position: relative;
  font-size: 0.95rem;
}

.output-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
  gap: 8px;
}

.output-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--subtext);
}

.copy-btn {
  background: var(--primary);
  color: white;
  border: none;
  padding: 5px 10px;
  border-radius: 999px;
  cursor: pointer;
  font-size: 0.75rem;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.copy-btn.copied {
  background: #16a34a;
}

/* Responsive */

@media (max-width: 768px) {
  .app {
    padding: 18px 16px 16px;
  }
  .app-header {
    flex-direction: column;
    align-items: flex-start;
  }
  .mode-row {
    flex-direction: column;
    align-items: flex-start;
  }
  .options-row {
    flex-direction: column;
    align-items: flex-start;
  }
/* ============================
   ⭐ FULL RESPONSIVE UPGRADE
   ============================ */

@media (max-width: 768px) {

  body {
    padding: 12px;
  }

  .shell {
    flex-direction: column;
    gap: 12px;
  }

  .app {
    padding: 16px 14px;
  }

  /* Header stacks */
  .app-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
  }

  .left-header {
    width: 100%;
    justify-content: space-between;
  }

  /* Login bar stacks vertically */
  .login-bar,
  .login-bar input,
  .login-bar button {
    width: 100%;
  }

  .login-bar {
    display: flex;
    flex-direction: column;
    gap: 8px !important;
  }

  /* Mode + length controls stack */
  .mode-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
  }

  /* Tone + generate button stack */
  .options-row {
    flex-direction: column;
    align-items: stretch;
    gap: 14px;
  }

  .select-group {
    width: 100%;
  }

  select {
    width: 100%;
  }

  #generateBtn {
    width: 100%;
    justify-content: center;
  }

  /* Textarea full width */
  textarea {
    min-height: 180px;
  }

  /* Output cards full width */
  .output-card {
    font-size: 0.9rem;
  }

  /* Sidebar covers full screen */
  .sidebar {
    width: 85%;
    max-width: 320px;
  }

  .sidebar-toggle {
    padding: 8px 12px;
    font-size: 0.9rem;
  }
}
}