/* ==========================================================================
   Base Styles & Layout
   ========================================================================== */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

html, body {
  min-height: 100vh;
  width: 100%;
  font-family: var(--font-sans);
  color: var(--text-primary);
  background: var(--bg-gradient);
  background-attachment: fixed;
  overflow-x: hidden;
  transition: background 0.3s ease, color 0.3s ease;
}

body {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 24px 16px;
  position: relative;
}

/* Ambient dynamic background lighting */
.ambient-glow {
  position: fixed;
  border-radius: 50%;
  filter: blur(100px);
  pointer-events: none;
  z-index: 0;
  opacity: 0.8;
  animation: pulseGlow 10s ease-in-out infinite alternate;
}

.ambient-glow-1 {
  width: 500px;
  height: 500px;
  top: -100px;
  left: -100px;
  background: var(--ambient-glow-1);
}

.ambient-glow-2 {
  width: 550px;
  height: 550px;
  bottom: -120px;
  right: -120px;
  background: var(--ambient-glow-2);
  animation-delay: -5s;
}

@keyframes pulseGlow {
  0% { transform: scale(1) translate(0, 0); }
  50% { transform: scale(1.15) translate(20px, 30px); }
  100% { transform: scale(0.95) translate(-20px, -20px); }
}

/* App Shell Container */
.app-container {
  width: 100%;
  max-width: 530px;
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 16px;
  transition: max-width 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

.app-container.sci-open {
  max-width: 1200px;
}

/* App Header & Navigation Bar (Merged Unified Header) */
.app-header {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 8px 14px;
  border-radius: var(--radius-lg);
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  box-shadow: var(--panel-shadow);
  position: relative;
}

.brand-badge {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.brand-icon {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, #6366f1, #d946ef);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 10px rgba(139, 92, 246, 0.3);
  flex-shrink: 0;
}

.brand-icon svg {
  width: 16px;
  height: 16px;
  stroke: #ffffff;
}

.brand-title {
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--text-primary), var(--text-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 0;
}

/* Merged Segmented Tab Navigation inside Header */
.tab-nav {
  display: inline-flex;
  align-items: center;
  background: rgba(0, 0, 0, 0.28);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-full);
  padding: 2.5px;
  gap: 2px;
  box-shadow: inset 0 2px 5px rgba(0, 0, 0, 0.3);
}

[data-theme="light"] .tab-nav {
  background: rgba(0, 0, 0, 0.05);
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.08);
}

.tab-btn {
  padding: 5px 11px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  white-space: nowrap;
}

.tab-btn svg {
  width: 14px;
  height: 14px;
  stroke: currentColor;
  flex-shrink: 0;
}

.tab-btn:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.06);
}

.tab-btn.active {
  background: var(--btn-num-bg);
  color: var(--text-primary);
  border-color: var(--panel-border);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.25);
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 5px;
  flex-shrink: 0;
}

/* Icon Buttons in Header */
.icon-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-secondary);
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.icon-btn svg {
  width: 16px;
  height: 16px;
  stroke: currentColor;
}

.icon-btn:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--panel-border);
  transform: translateY(-1px);
}

.icon-btn:active {
  transform: translateY(1px);
}

.icon-btn.active {
  color: var(--sound-active-color);
  background: rgba(16, 185, 129, 0.12);
  border-color: rgba(16, 185, 129, 0.3);
}

/* Main and Tab Views */
main {
  width: 100%;
}

.tab-view {
  width: 100%;
  display: none;
  animation: fadeIn 0.25s ease-out forwards;
}

.tab-view.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Tooltip / Toast Notification */
.toast-notice {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(50px);
  opacity: 0;
  background: var(--drawer-bg);
  border: 1px solid var(--panel-border);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
  color: var(--text-primary);
  padding: 10px 20px;
  border-radius: var(--radius-full);
  font-size: 0.88rem;
  font-weight: 500;
  z-index: 100;
  pointer-events: none;
  transition: all 0.25s var(--transition-bounce);
  backdrop-filter: blur(12px);
}

.toast-notice.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* Responsive adjustment */
@media (max-width: 460px) {
  .brand-title {
    display: none;
  }
}

@media (max-width: 440px) {
  body {
    padding: 10px 8px;
  }
  .app-container {
    gap: 12px;
  }
  .app-header {
    padding: 6px 8px;
    gap: 6px;
  }
  .tab-btn {
    font-size: 0.78rem;
    padding: 5px 8px;
    gap: 4px;
  }
  .tab-btn svg {
    width: 14px;
    height: 14px;
  }
  .icon-btn {
    width: 32px;
    height: 32px;
  }
  .icon-btn svg {
    width: 16px;
    height: 16px;
  }
}