/* ============================================================
   Streamlined & Innovative Button System
   ------------------------------------------------------------
   - Unifies every button/CTA class across the app
   - Uses existing design tokens so it adapts to dark & light themes
   - WCAG AA contrast, 44px min touch targets, visible focus rings
   - Full ARIA-state styling (:disabled, aria-pressed, aria-expanded,
     aria-busy)
   - Loaded LAST in base.html so it cleanly overrides legacy rules
   ============================================================ */

:root {
  --btn-radius: 12px;
  --btn-radius-pill: 999px;
  --btn-min-size: 44px; /* WCAG 2.5.5 target size */
  --btn-pad-y: 0.7rem;
  --btn-pad-x: 1.25rem;
  --btn-font-weight: 600;

  /* Dedicated, distinct button palette (NOT the legacy --color-primary blue)
     so the streamlined restyle is clearly visible. Teal-forward primary. */
  --btn-primary-bg: #0d9488;          /* teal-600 */
  --btn-primary-bg-hover: #0f766e;    /* teal-700 */
  --btn-primary-fg: #ffffff;
  --btn-accent: #14b8a6;              /* teal-500 sheen accent */

  --btn-ring: 0 0 0 3px color-mix(in srgb, var(--btn-primary-bg) 50%, transparent);
  --btn-shadow: 0 1px 2px rgba(0, 0, 0, 0.18), 0 4px 12px rgba(13, 148, 136, 0.18);
  --btn-shadow-hover: 0 2px 4px rgba(0, 0, 0, 0.22), 0 10px 24px rgba(13, 148, 136, 0.28);
  --btn-transition: 180ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ------------------------------------------------------------
   Shared foundation for all button variants
   ------------------------------------------------------------ */
.btn,
.auth-btn,
.send-btn,
.file-upload-btn,
.new-chat-btn,
.ellipsis-btn,
.theme-toggle-btn,
.tts-toggle-btn,
.sidebar-toggle,
.retry-button,
.cta-button,
.back-button,
.home-button,
.details-toggle,
.submit-quiz-btn,
.replay-quiz-btn,
.quiz-nav-btn,
.btn-primary,
.btn-secondary,
.btn-danger,
.btn-success,
.btn-info,
.btn-login,
.btn-register,
.btn-leaderboard {
  --_btn-bg: var(--btn-primary-bg);
  --_btn-bg-hover: var(--btn-primary-bg-hover);
  --_btn-fg: var(--btn-primary-fg);
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: var(--btn-min-size);
  padding: var(--btn-pad-y) var(--btn-pad-x);
  border: 1px solid transparent;
  border-radius: var(--btn-radius);
  font-family: var(--font-sans, inherit);
  font-size: 0.9375rem;
  font-weight: var(--btn-font-weight);
  line-height: 1.2;
  text-align: center;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  background-color: var(--_btn-bg);
  color: var(--_btn-fg);
  box-shadow: var(--btn-shadow);
  transition: background-color var(--btn-transition), border-color var(--btn-transition),
    box-shadow var(--btn-transition), transform var(--btn-transition), opacity var(--btn-transition);
}

/* Innovative subtle top-sheen for depth without heavy gradients */
.btn::after,
.auth-btn::after,
.send-btn::after,
.cta-button::after,
.btn-primary::after,
.submit-quiz-btn::after,
.replay-quiz-btn::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.16), rgba(255, 255, 255, 0));
  opacity: 0.9;
  pointer-events: none;
}

/* Hover / active motion */
.btn:hover:not(:disabled):not([aria-disabled="true"]),
.auth-btn:hover:not(:disabled),
.send-btn:hover:not(:disabled),
.file-upload-btn:hover:not(:disabled),
.new-chat-btn:hover:not(:disabled),
.ellipsis-btn:hover:not(:disabled),
.theme-toggle-btn:hover:not(:disabled),
.tts-toggle-btn:hover:not(:disabled),
.sidebar-toggle:hover:not(:disabled),
.retry-button:hover:not(:disabled),
.cta-button:hover:not(:disabled),
.back-button:hover:not(:disabled),
.home-button:hover:not(:disabled),
.details-toggle:hover:not(:disabled),
.submit-quiz-btn:hover:not(:disabled),
.replay-quiz-btn:hover:not(:disabled),
.quiz-nav-btn:hover:not(:disabled),
.btn-primary:hover:not(:disabled),
.btn-secondary:hover:not(:disabled),
.btn-danger:hover:not(:disabled),
.btn-success:hover:not(:disabled),
.btn-info:hover:not(:disabled),
.btn-leaderboard:hover:not(:disabled) {
  background-color: var(--_btn-bg-hover);
  box-shadow: var(--btn-shadow-hover);
  transform: translateY(-1px);
}

.btn:active:not(:disabled),
.auth-btn:active:not(:disabled),
.send-btn:active:not(:disabled),
.cta-button:active:not(:disabled),
.retry-button:active:not(:disabled),
.btn-primary:active:not(:disabled),
.btn-secondary:active:not(:disabled),
.btn-danger:active:not(:disabled),
.submit-quiz-btn:active:not(:disabled),
.replay-quiz-btn:active:not(:disabled),
.quiz-nav-btn:active:not(:disabled) {
  transform: translateY(0);
  box-shadow: var(--btn-shadow);
}

/* ------------------------------------------------------------
   Accessible focus ring (keyboard) for every variant
   ------------------------------------------------------------ */
.btn:focus-visible,
.auth-btn:focus-visible,
.send-btn:focus-visible,
.file-upload-btn:focus-visible,
.new-chat-btn:focus-visible,
.ellipsis-btn:focus-visible,
.theme-toggle-btn:focus-visible,
.tts-toggle-btn:focus-visible,
.sidebar-toggle:focus-visible,
.retry-button:focus-visible,
.cta-button:focus-visible,
.back-button:focus-visible,
.home-button:focus-visible,
.details-toggle:focus-visible,
.submit-quiz-btn:focus-visible,
.replay-quiz-btn:focus-visible,
.quiz-nav-btn:focus-visible,
.btn-primary:focus-visible,
.btn-secondary:focus-visible,
.btn-danger:focus-visible,
.btn-success:focus-visible,
.btn-info:focus-visible,
.btn-leaderboard:focus-visible {
  outline: 2px solid transparent;
  outline-offset: 2px;
  box-shadow: var(--btn-ring), var(--btn-shadow);
}

/* ------------------------------------------------------------
   Disabled / busy states (ARIA-aware)
   ------------------------------------------------------------ */
.btn:disabled,
.btn[aria-disabled="true"],
.auth-btn:disabled,
.send-btn:disabled,
.submit-quiz-btn:disabled,
.quiz-nav-btn:disabled,
.btn-primary:disabled,
.btn-secondary:disabled,
.btn-danger:disabled,
.retry-button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

[aria-busy="true"].btn,
[aria-busy="true"].auth-btn,
[aria-busy="true"].send-btn {
  cursor: progress;
}

/* ------------------------------------------------------------
   Color variants (semantic, high-contrast on both themes)
   ------------------------------------------------------------ */
.btn-secondary,
.back-button,
.quiz-nav-btn {
  --_btn-bg: var(--color-surface-elevated);
  --_btn-bg-hover: var(--color-border);
  --_btn-fg: var(--color-text-primary);
  border-color: var(--color-border);
}

.btn-danger {
  --_btn-bg: var(--color-danger);
  --_btn-bg-hover: color-mix(in srgb, var(--color-danger) 85%, #000);
  --_btn-fg: #ffffff;
}

.btn-success,
.submit-quiz-btn {
  --_btn-bg: var(--color-success);
  --_btn-bg-hover: color-mix(in srgb, var(--color-success) 85%, #000);
  --_btn-fg: #ffffff;
}

.btn-info,
.btn-leaderboard {
  --_btn-bg: var(--btn-primary-bg);
  --_btn-bg-hover: var(--btn-primary-bg-hover);
  --_btn-fg: var(--btn-primary-fg);
}

/* ------------------------------------------------------------
   Icon-only buttons: keep them square, centered, pill-friendly
   ------------------------------------------------------------ */
.send-btn,
.file-upload-btn,
.ellipsis-btn,
.theme-toggle-btn,
.tts-toggle-btn,
.sidebar-toggle {
  min-width: var(--btn-min-size);
  padding: 0.6rem;
  aspect-ratio: 1 / 1;
}

.ellipsis-btn,
.theme-toggle-btn,
.tts-toggle-btn,
.sidebar-toggle,
.file-upload-btn {
  --_btn-bg: var(--color-surface-elevated);
  --_btn-bg-hover: var(--color-border);
  --_btn-fg: var(--color-text-primary);
  border-color: var(--color-border);
  box-shadow: none;
}

.ellipsis-btn:hover:not(:disabled),
.theme-toggle-btn:hover:not(:disabled),
.tts-toggle-btn:hover:not(:disabled),
.sidebar-toggle:hover:not(:disabled),
.file-upload-btn:hover:not(:disabled) {
  box-shadow: none;
  transform: translateY(-1px);
}

/* Toggle "on" state via ARIA pressed — clear active affordance */
.tts-toggle-btn[aria-pressed="true"],
.theme-toggle-btn[aria-pressed="true"],
.practice-mode-toggle[aria-pressed="true"] {
  --_btn-bg: var(--btn-primary-bg);
  --_btn-fg: var(--btn-primary-fg);
  border-color: var(--btn-primary-bg);
}

/* Expander arrow rotation tied to aria-expanded */
.details-toggle .toggle-arrow {
  transition: transform var(--btn-transition);
}
.details-toggle[aria-expanded="true"] .toggle-arrow {
  transform: rotate(180deg);
}

/* New-chat lives inside the sidebar list — make it a full-width pill */
.sidebar-link.new-chat-btn {
  width: 100%;
  justify-content: flex-start;
  border-radius: var(--btn-radius);
}

/* CTAs read as prominent pills */
.cta-button,
.auth-btn {
  border-radius: var(--btn-radius-pill);
}
.auth-btn {
  width: 100%;
}

/* Keep Material icons optically centered */
.btn .material-symbols-outlined,
.theme-toggle-btn .material-symbols-outlined,
.tts-toggle-btn .material-symbols-outlined,
.sidebar-toggle .material-symbols-outlined {
  font-size: 1.375rem;
  line-height: 1;
}

/* ------------------------------------------------------------
   Mobile responsiveness
   ------------------------------------------------------------ */
@media (max-width: 640px) {
  .btn,
  .auth-btn,
  .cta-button,
  .submit-quiz-btn,
  .replay-quiz-btn,
  .btn-danger,
  .btn-secondary {
    width: 100%;
  }

  .button-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
  }

  /* Keep icon-only controls compact, not full width */
  .send-btn,
  .file-upload-btn,
  .ellipsis-btn,
  .theme-toggle-btn,
  .tts-toggle-btn,
  .sidebar-toggle {
    width: var(--btn-min-size);
  }
}

/* ------------------------------------------------------------
   Respect user motion preferences
   ------------------------------------------------------------ */
@media (prefers-reduced-motion: reduce) {
  .btn,
  .auth-btn,
  .send-btn,
  .cta-button,
  .btn-primary,
  .btn-secondary,
  .btn-danger,
  .submit-quiz-btn,
  .replay-quiz-btn,
  .quiz-nav-btn,
  .details-toggle .toggle-arrow {
    transition: none;
  }
  .btn:hover,
  .auth-btn:hover,
  .cta-button:hover {
    transform: none;
  }
}

/* ------------------------------------------------------------
   Forced-colors / high-contrast (Windows) support
   ------------------------------------------------------------ */
@media (forced-colors: active) {
  .btn,
  .auth-btn,
  .send-btn,
  .cta-button,
  .btn-primary,
  .btn-secondary,
  .btn-danger,
  .submit-quiz-btn,
  .replay-quiz-btn,
  .quiz-nav-btn {
    border: 1px solid ButtonText;
  }
  .btn:focus-visible,
  .auth-btn:focus-visible,
  .send-btn:focus-visible,
  .cta-button:focus-visible {
    outline: 2px solid Highlight;
  }
}

/* ------------------------------------------------------------
   Navbar auth link-buttons (Login / Register / Get Started)
   These are <a> elements, not <button>, so they need explicit
   targeting to match the streamlined teal system.
   ------------------------------------------------------------ */

/* Primary navbar CTA: Register / Get Started */
.auth-nav-link.auth-nav-link--primary,
.nav-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  min-height: var(--btn-min-size);
  padding: var(--btn-pad-y) var(--btn-pad-x);
  border: 1px solid transparent;
  border-radius: var(--btn-radius-pill);
  background: var(--btn-primary-bg);
  color: var(--btn-primary-fg) !important;
  font-weight: var(--btn-font-weight);
  text-decoration: none;
  line-height: 1;
  box-shadow: var(--btn-shadow);
  transition: background var(--btn-transition), transform var(--btn-transition),
    box-shadow var(--btn-transition);
}

.auth-nav-link.auth-nav-link--primary:hover,
.nav-cta:hover {
  background: var(--btn-primary-bg-hover);
  color: var(--btn-primary-fg) !important;
  transform: translateY(-1px);
  box-shadow: var(--btn-shadow-hover);
}

.auth-nav-link.auth-nav-link--primary:active,
.nav-cta:active {
  transform: translateY(0);
  box-shadow: var(--btn-shadow);
}

.auth-nav-link.auth-nav-link--primary:focus-visible,
.nav-cta:focus-visible {
  outline: none;
  box-shadow: var(--btn-shadow), var(--btn-ring);
}

/* Secondary navbar link: Login — streamlined outlined pill */
.auth-navbar-actions .auth-nav-link:not(.auth-nav-link--primary),
.nav-links .nav-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  min-height: var(--btn-min-size);
  padding: var(--btn-pad-y) var(--btn-pad-x);
  border-radius: var(--btn-radius-pill);
  transition: color var(--btn-transition), background var(--btn-transition),
    box-shadow var(--btn-transition);
}

.auth-navbar-actions .auth-nav-link:not(.auth-nav-link--primary):hover,
.nav-links .nav-link:hover {
  color: var(--btn-primary-bg);
  background: color-mix(in srgb, var(--btn-primary-bg) 12%, transparent);
}

.auth-navbar-actions .auth-nav-link:not(.auth-nav-link--primary):focus-visible,
.nav-links .nav-link:focus-visible {
  outline: none;
  box-shadow: var(--btn-ring);
}

@media (forced-colors: active) {
  .auth-nav-link.auth-nav-link--primary,
  .nav-cta {
    border: 1px solid ButtonText;
  }
}

/* ------------------------------------------------------------
   Chatbot navbar auth links (Login / Sign Up)
   Classes: .navbar-auth-link and .navbar-auth-link--primary
   These are <a> elements with legacy blue + forced white text,
   so they need explicit targeting (including theme overrides).
   ------------------------------------------------------------ */

/* Secondary navbar link: Login — streamlined outlined pill */
.navbar-auth-link {
  min-height: var(--btn-min-size);
  padding: 0.55rem 1.1rem;
  border-radius: var(--btn-radius-pill);
  font-weight: var(--btn-font-weight);
  transition: color var(--btn-transition), background var(--btn-transition),
    border-color var(--btn-transition), transform var(--btn-transition),
    box-shadow var(--btn-transition);
}

.navbar-auth-link:focus-visible {
  outline: none;
  box-shadow: var(--btn-ring);
}

/* Primary navbar CTA: Sign Up — teal fill matching the button system */
.navbar-auth-link.navbar-auth-link--primary,
[data-theme="light"] .navbar-auth-link.navbar-auth-link--primary {
  background: var(--btn-primary-bg);
  color: var(--btn-primary-fg) !important;
  border-color: var(--btn-primary-bg);
  box-shadow: var(--btn-shadow);
}

.navbar-auth-link.navbar-auth-link--primary:hover,
[data-theme="light"] .navbar-auth-link.navbar-auth-link--primary:hover {
  background: var(--btn-primary-bg-hover);
  color: var(--btn-primary-fg) !important;
  border-color: var(--btn-primary-bg-hover);
  transform: translateY(-1px);
  box-shadow: var(--btn-shadow-hover);
}

.navbar-auth-link.navbar-auth-link--primary:active {
  transform: translateY(0);
  box-shadow: var(--btn-shadow);
}

@media (forced-colors: active) {
  .navbar-auth-link.navbar-auth-link--primary {
    border: 1px solid ButtonText;
  }
}