:root {
  /* M3 Indigo/Violet Tonal Palette (Light Theme) */
  --m3-primary: #5256a9;
  --m3-on-primary: #ffffff;
  --m3-primary-container: #e1e0ff;
  --m3-on-primary-container: #080762;
  
  --m3-secondary: #5c5d72;
  --m3-on-secondary: #ffffff;
  --m3-secondary-container: #e1e0f9;
  --m3-on-secondary-container: #191a2c;
  
  --m3-tertiary: #78536b;
  --m3-on-tertiary: #ffffff;
  --m3-tertiary-container: #ffd8ee;
  --m3-on-tertiary-container: #2e1126;

  --m3-error: #ba1a1a;
  --m3-on-error: #ffffff;
  --m3-error-container: #ffdad6;
  --m3-on-error-container: #410002;

  --m3-surface: #fdfbff;
  --m3-on-surface: #1b1b1f;
  --m3-surface-variant: #e4e1ec;
  --m3-on-surface-variant: #46464f;
  
  --m3-outline: #777680;
  --m3-outline-variant: #c8c5d0;

  --m3-surface-container-low: #f7f2fa;
  --m3-surface-container: #f3edf7;
  --m3-surface-container-high: #ece6f0;
  --m3-surface-container-highest: #e6e0e9;

  /* M3 Motion Tokens */
  --m3-duration-short: 150ms;
  --m3-duration-medium: 250ms;
  --m3-duration-long: 400ms;
  
  --m3-easing-standard: cubic-bezier(0.2, 0, 0, 1);
  --m3-easing-emphasized: cubic-bezier(0.2, 0, 0, 1);
  --m3-easing-emphasized-decelerate: cubic-bezier(0.05, 0.7, 0.1, 1);
  --m3-easing-emphasized-accelerate: cubic-bezier(0.3, 0, 0.8, 0.15);

  /* M3 Elevation (Shadows + Tonal Overlays) */
  --m3-elevation-1: 0px 1px 2px 0px rgba(0,0,0,0.3), 0px 1px 3px 1px rgba(0,0,0,0.15);
  --m3-elevation-2: 0px 1px 2px 0px rgba(0,0,0,0.3), 0px 2px 6px 2px rgba(0,0,0,0.15);
  --m3-elevation-3: 0px 4px 8px 3px rgba(0,0,0,0.15), 0px 1px 3px 0px rgba(0,0,0,0.3);
}

.m3-dark-theme {
  --m3-primary: #c0c1ff;
  --m3-on-primary: #222578;
  --m3-primary-container: #3a3d8f;
  --m3-on-primary-container: #e1e0ff;
  
  --m3-secondary: #c5c4dd;
  --m3-on-secondary: #2e2f42;
  --m3-secondary-container: #444559;
  --m3-on-secondary-container: #e1e0f9;
  
  --m3-surface: #1b1b1f;
  --m3-on-surface: #e4e1e6;
  --m3-outline: #938f99;
  --m3-outline-variant: #49454f;
  
  --m3-surface-container-low: #1d1b20;
  --m3-surface-container: #211f26;
  --m3-surface-container-high: #2b2930;
  --m3-surface-container-highest: #36343b;
}

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

body {
  font-family: 'Roboto', sans-serif;
  background-color: var(--m3-surface);
  color: var(--m3-on-surface);
  line-height: 1.5;
  overflow: hidden;
  height: 100dvh;
}

/* Material Typography */
.m3-title-large { font-size: 22px; font-weight: 400; }
.m3-title-medium { font-size: 16px; font-weight: 500; letter-spacing: 0.15px; }
.m3-title-small { font-size: 14px; font-weight: 500; letter-spacing: 0.1px; }
.m3-label-large { font-size: 14px; font-weight: 500; letter-spacing: 0.1px; }
.m3-label-medium { font-size: 12px; font-weight: 500; letter-spacing: 0.5px; }
.m3-body-large { font-size: 16px; font-weight: 400; letter-spacing: 0.5px; }
.m3-body-medium { font-size: 14px; font-weight: 400; letter-spacing: 0.25px; }
.m3-headline-small { font-size: 24px; font-weight: 400; }

/* Interactive State Layers */
.m3-state-layer {
  position: absolute;
  inset: 0;
  background-color: currentColor;
  opacity: 0;
  transition: opacity var(--m3-duration-short) var(--m3-easing-standard);
  pointer-events: none;
}

button:hover .m3-state-layer, 
.m3-interactive:hover .m3-state-layer { opacity: 0.08; }
button:active .m3-state-layer,
.m3-interactive:active .m3-state-layer { opacity: 0.12; }
button:focus .m3-state-layer,
.m3-interactive:focus .m3-state-layer { opacity: 0.12; }

/* Global Ripple Effect */
.m3-ripple-container {
    position: relative;
    overflow: hidden;
}

.m3-ripple {
    position: absolute;
    border-radius: 50%;
    background-color: currentColor;
    opacity: 0.12;
    transform: scale(0);
    animation: m3-ripple-animation 600ms var(--m3-easing-standard) forwards;
    pointer-events: none;
}

@keyframes m3-ripple-animation {
    to { transform: scale(4); opacity: 0; }
}

/* Layout Containers */
.m3-container {
  display: grid;
  grid-template-columns: 360px 1fr;
  height: 100dvh;
  width: 100%;
  overflow: hidden;
}

@media (max-width: 900px) {
  .m3-container { grid-template-columns: 1fr; }
}

/* Navigation Drawer */
.m3-navigation-drawer {
  background-color: var(--m3-surface-container);
  border-right: 1px solid var(--m3-outline-variant);
  padding: 12px;
  display: flex;
  flex-direction: column;
  z-index: 10;
  transition: transform var(--m3-duration-long) var(--m3-easing-emphasized);
}

@media (max-width: 900px) {
  .m3-navigation-drawer {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: 320px;
    transform: translateX(-100%);
    box-shadow: var(--m3-elevation-3);
    z-index: 100;
  }
  .m3-navigation-drawer.open { transform: translateX(0) !important; }
}

.drawer-header { padding: 16px; margin-bottom: 8px; }
.drawer-content { flex: 1; overflow-y: auto; padding: 0 12px; }
.drawer-footer { padding: 12px; border-top: 1px solid var(--m3-outline-variant); }

/* Chat Item */
.chat-item {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 12px 16px;
  margin-bottom: 4px;
  border-radius: 16px;
  cursor: pointer;
  color: var(--m3-on-surface-variant);
  transition: all var(--m3-duration-short) var(--m3-easing-standard);
}

.chat-item.active {
  background-color: var(--m3-secondary-container);
  color: var(--m3-on-secondary-container);
}

.chat-item .chat-name { font-weight: 500; margin-bottom: 4px; }
.chat-item .chat-preview { font-size: 12px; opacity: 0.7; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* Main Content Area */
.m3-main {
  display: flex;
  flex-direction: column;
  background-color: var(--m3-surface);
  position: relative;
  height: 100%;
  min-height: 0;
  overflow: hidden;
}

.m3-top-app-bar {
  height: 64px;
  display: flex;
  align-items: center;
  padding: 0 16px;
  background-color: var(--m3-surface);
  border-bottom: 1px solid var(--m3-outline-variant);
  gap: 8px;
  z-index: 5;
}

.m3-chat-history {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-height: 0;
  -webkit-overflow-scrolling: touch;
}

/* Message Bubbles */
.message {
  max-width: 85%;
  padding: 12px 16px;
  border-radius: 16px;
  position: relative;
  animation: m3-message-entry 300ms var(--m3-easing-emphasized-decelerate);
}

@keyframes m3-message-entry {
  from { transform: translateY(10px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

.message.user {
  align-self: flex-end;
  background-color: var(--m3-primary-container);
  color: var(--m3-on-primary-container);
  border-bottom-right-radius: 4px;
}

.message.ai {
  align-self: flex-start;
  background-color: var(--m3-surface-container-high);
  color: var(--m3-on-surface);
  border-bottom-left-radius: 4px;
  padding-bottom: 32px;
}

.msg-actions {
  position: absolute;
  top: 4px;
  right: 4px;
  display: flex;
  gap: 4px;
  opacity: 0;
  transition: opacity var(--m3-duration-short) var(--m3-easing-standard);
  z-index: 2;
}

.message:hover .msg-actions { opacity: 1; }

/* Always low-opacity on touch */
@media (hover: none) {
    .msg-actions { opacity: 0.6; }
}

.delete-msg-btn {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  background-color: var(--m3-surface-container-highest);
  color: var(--m3-error);
  border: none;
  font-size: 18px;
  box-shadow: var(--m3-elevation-1);
}

.delete-msg-btn:hover {
    background-color: var(--m3-error-container);
    color: var(--m3-on-error-container);
}

/* Typing Cursor Animation */
.typing-cursor::after {
  content: '|';
  display: inline-block;
  margin-left: 2px;
  color: var(--m3-primary);
  animation: m3-cursor-blink 800ms infinite;
}

@keyframes m3-cursor-blink {
  0%, 100% { opacity: 0; }
  50% { opacity: 1; }
}

.message-editor {
  width: 100%;
  background: none;
  border: 1px solid var(--m3-outline);
  border-radius: 8px;
  color: inherit;
  font-family: inherit;
  font-size: inherit;
  padding: 8px;
  min-height: 100px;
  outline: none;
  resize: vertical;
}

.message-editor:focus { border-color: var(--m3-primary); }

.edit-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  margin-top: 8px;
}

/* Generation Pager */
.gen-pager {
  position: absolute;
  bottom: 4px;
  right: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 11px;
  opacity: 0.6;
}

.pager-btn {
  background: none;
  border: none;
  cursor: pointer;
  color: inherit;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4px;
  border-radius: 50%;
}

.pager-btn:hover { background-color: rgba(0,0,0,0.1); }

/* M3 Buttons */
.m3-button-filled {
  height: 40px;
  padding: 0 24px;
  background-color: var(--m3-primary);
  color: var(--m3-on-primary);
  border: none;
  border-radius: 20px;
  font-weight: 500;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.m3-button-tonal {
  background-color: var(--m3-secondary-container);
  color: var(--m3-on-secondary-container);
}

.m3-button-text {
  height: 40px;
  padding: 0 12px;
  background: none;
  border: none;
  color: var(--m3-primary);
  border-radius: 20px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.m3-icon-button {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--m3-on-surface-variant);
  background: none;
  border: none;
  position: relative;
  overflow: hidden;
}

/* Chat Footer / Input */
.m3-chat-footer {
  padding: 12px 16px;
  background-color: var(--m3-surface);
}

.m3-text-field-container {
  display: flex;
  align-items: flex-end;
  gap: 8px;
  background-color: var(--m3-surface-container-high);
  padding: 4px 8px 4px 16px;
  border-radius: 28px;
  transition: background-color var(--m3-duration-short) var(--m3-easing-standard);
}

.m3-text-field-container:focus-within {
    background-color: var(--m3-surface-container-highest);
    box-shadow: 0 0 0 2px var(--m3-primary);
}

.m3-text-field {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  padding: 12px 0;
  font-size: 16px;
  color: var(--m3-on-surface);
  resize: none;
  max-height: 200px;
}

/* Modals / Dialogs */
.m3-modal-overlay {
  position: fixed;
  inset: 0;
  background-color: rgba(0,0,0,0.4);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 100;
  backdrop-filter: blur(2px);
}

.m3-dialog {
  background-color: var(--m3-surface-container-high);
  width: 90%;
  max-width: 560px;
  max-height: 90dvh;
  border-radius: 28px;
  overflow: hidden;
  box-shadow: var(--m3-elevation-3);
  animation: m3-dialog-entry 400ms var(--m3-easing-emphasized);
  display: flex;
  flex-direction: column;
}

@keyframes m3-dialog-entry {
  from { transform: scale(0.9); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

.m3-dialog-content { 
    padding: 24px; 
    overflow-y: auto;
    flex: 1;
}
.m3-dialog-actions { 
  display: flex; 
  justify-content: flex-end; 
  gap: 8px; 
  margin-top: 24px;
}

.selection-list { display: flex; flex-direction: column; gap: 4px; margin-top: 16px; }

.selection-item {
  position: relative;
  padding: 8px 16px;
  min-height: 56px;
  border-radius: 12px;
  cursor: pointer;
  background-color: var(--m3-surface-container);
  display: flex;
  align-items: center;
  gap: 12px;
}

.selection-item-content {
    flex: 1;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.selection-item-actions {
    display: flex;
    gap: 4px;
}

.selection-item.active {
    background-color: var(--m3-primary-container);
    color: var(--m3-on-primary-container);
}

/* Markdown Support */
.message span { display: block; word-break: break-word; }
.message strong { color: var(--m3-primary); }
.message p { margin-bottom: 8px; }
.message p:last-child { margin-bottom: 0; }
.message code { background: rgba(0,0,0,0.1); padding: 2px 4px; border-radius: 4px; font-family: monospace; }
.message pre { background: rgba(0,0,0,0.1); padding: 12px; border-radius: 8px; overflow-x: auto; margin: 8px 0; }

.hide-desktop { display: none; }
@media (max-width: 900px) {
  .hide-desktop { display: flex; }
}