:root {
      --bg-primary: #0d0d0d;
      --bg-secondary: #1a1a1a;
      --bg-tertiary: #2a2a2a;
      --text-primary: #f2f2f2;
      --text-secondary: #cccccc;
      --text-muted: #888888;
      --accent: #888888;
      --accent-hover: #bbbbbb;
      --border: #333333;
      --shadow: rgba(0, 0, 0, 0.8);
      --code-bg: #111111;
      --code-text: #f5f5f5;

      --js-color: #f7df1e;
      --html-color: #e34f26;
      --css-color: #1572b6;
      --cpp-color: #00599c;

      --gradient-1: linear-gradient(135deg, #8a8a8a 0%, #575757 100%);
      --gradient-2: linear-gradient(135deg, #999999 0%, #666666 100%);
      --gradient-3: linear-gradient(135deg, #b0b0b0 0%, #777777 100%);
      --gradient-4: linear-gradient(135deg, #c8c8c8 0%, #888888 100%);
      --gradient-vibe: linear-gradient(90deg, #333333, #666666, #444444, #222222);

      --space-xs: 0.5rem;
      --space-sm: 1rem;
      --space-md: 1.5rem;
      --space-lg: 2rem;
      --space-xl: 3rem;
      --space-xxl: 5rem;

      --text-xs: 0.75rem;
      --text-sm: 0.875rem;
      --text-base: 1rem;
      --text-lg: 1.125rem;
      --text-xl: 1.25rem;
      --text-2xl: 1.5rem;
      --text-3xl: 1.875rem;
      --text-4xl: 2.25rem;
      --text-5xl: 3rem;
      --text-6xl: 3.75rem;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    }

    body {
      min-height: 100vh;
      background: var(--bg-primary);
      color: var(--text-primary);
    }

    .app {
      min-height: 100vh;
      width: 100%;
      background:
        radial-gradient(circle at top, rgba(255, 255, 255, 0.06), transparent 55%),
        var(--bg-primary);
      display: flex;
      flex-direction: column;
    }

    /* HEADER */

    .header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 10px;
      padding: 10px 16px;
      border-bottom: 1px solid var(--border);
      background: linear-gradient(
        180deg,
        var(--bg-secondary),
        var(--bg-primary)
      );
    }

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

    .nav-toggle {
      width: 32px;
      height: 32px;
      border-radius: 999px;
      border: 1px solid var(--border);
      background: var(--bg-primary);
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      transition: 0.16s ease;
    }

    .nav-toggle:hover {
      border-color: var(--accent-hover);
      box-shadow: 0 0 0 1px var(--shadow);
    }

    .nav-toggle svg {
      width: 18px;
      height: 18px;
      stroke: var(--text-primary);
    }

    .title-wrap {
      display: flex;
      flex-direction: column;
      gap: 2px;
    }

    .title-row {
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .status-dot {
    width: 9px;
    height: 9px;
    border-radius: 999px;  
    background: #22c55e;
    box-shadow: 0 0 12px rgba(34, 197, 94, 0.7);
}

    .title-text {
      font-size: var(--text-lg);
      font-weight: 600;
      color: var(--text-primary);
    }

    .subtitle {
      font-size: var(--text-xs);
      color: var(--text-muted);
    }

    .header-right {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: var(--text-xs);
      color: var(--text-secondary);
    }

    .model-pill {
      padding: 3px 9px;
      border-radius: 999px;
      border: 1px solid var(--border);
      background: var(--bg-tertiary);
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }

    .model-pill svg {
      width: 13px;
      height: 13px;
      stroke: var(--text-muted);
    }

    /* QUICK ACTIONS */

    .quick-actions {
      padding: 6px 16px 8px;
      border-bottom: 1px solid var(--border);
      background: linear-gradient(
        180deg,
        var(--bg-secondary),
        var(--bg-primary)
      );
      display: flex;
      flex-wrap: wrap;
      gap: 6px;
    }

    .quick-chip {
      border-radius: 999px;
      padding: 4px 10px;
      font-size: var(--text-xs);
      border: 1px solid var(--border);
      background: var(--bg-tertiary);
      color: var(--text-secondary);
      display: inline-flex;
      align-items: center;
      gap: 6px;
      cursor: pointer;
      transition: 0.16s ease;
    }

    .quick-chip svg {
      width: 13px;
      height: 13px;
      stroke: var(--text-muted);
    }

    .quick-chip:hover {
      border-color: var(--accent-hover);
      color: var(--text-primary);
      background: var(--gradient-2);
    }

    /* CHAT AREA */

    .chat-area {
      flex: 1;
      display: flex;
      flex-direction: column;
      min-height: 0;
      background:
        var(--bg-primary);
    }

    .messages {
      flex: 1;
      padding: 14px 16px 10px;
      overflow-y: auto;
      scroll-behavior: smooth;
      scrollbar-width: thin;
      scrollbar-color: var(--border) transparent;
    }

    .messages::-webkit-scrollbar {
      width: 6px;
    }

    .messages::-webkit-scrollbar-track {
      background: transparent;
    }

    .messages::-webkit-scrollbar-thumb {
      background: var(--border);
      border-radius: 999px;
    }

    .message {
      display: flex;
      margin-bottom: 14px;
      animation: fadeIn 0.22s ease-out;
    }

    .message.user {
      justify-content: flex-end;
    }

    .message.assistant {
      justify-content: flex-start;
    }

    .bubble {
      max-width: min(720px, 100%);
      padding: 10px 12px;
      border-radius: 12px;
      border: 1px solid var(--border);
      background: var(--bg-secondary);
      font-size: var(--text-sm);
      line-height: 1.5;
      color: var(--text-primary);
      white-space: pre-wrap;
      word-wrap: break-word;
      position: relative;
      box-shadow: 0 8px 20px var(--shadow);
    }

    .message.assistant .bubble {
      background: var(--gradient-vibe);
    }

    .message.user .bubble {
      background: var(--bg-tertiary);
    }

    .bubble-header {
      font-size: var(--text-xs);
      color: var(--text-muted);
      margin-bottom: 4px;
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .bubble-header span.dot {
      width: 4px;
      height: 4px;
      border-radius: 999px;
      background: var(--border);
    }

    .bubble-content {
      margin-top: 2px;
    }

    .bubble-footer {
      margin-top: 6px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: var(--text-xs);
      color: var(--text-muted);
    }

    .bubble-actions {
      display: inline-flex;
      gap: 4px;
    }

    .bubble-btn {
      border: none;
      background: transparent;
      width: 20px;
      height: 20px;
      border-radius: 999px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      transition: 0.16s ease;
    }

    .bubble-btn svg {
      width: 13px;
      height: 13px;
      stroke: var(--text-muted);
    }

    .bubble-btn:hover {
      background: var(--bg-tertiary);
    }

    .bubble-btn:hover svg {
      stroke: var(--text-primary);
    }

    .code-block {
      margin-top: 8px;
      background: var(--code-bg);
      border-radius: 10px;
      border: 1px solid var(--border);
      padding: 10px;
      position: relative;
      overflow-x: auto;
      font-family: "Fira Code", ui-monospace, SFMono-Regular, Menlo, Monaco,
        Consolas, "Liberation Mono", "Courier New", monospace;
      font-size: 0.78rem;
      box-shadow: inset 0 0 22px rgba(0, 0, 0, 0.8);
      color: var(--code-text);
    }

    .code-lang {
      position: absolute;
      top: 0;
      left: 0;
      padding: 2px 8px;
      border-bottom-right-radius: 8px;
      font-size: 0.7rem;
      text-transform: uppercase;
      color: var(--text-secondary);
      background: var(--bg-tertiary);
      border-bottom: 1px solid var(--border);
      border-right: 1px solid var(--border);
    }

    .code-lang[data-lang="JS"] {
      color: var(--js-color);
    }
    .code-lang[data-lang="HTML"] {
      color: var(--html-color);
    }
    .code-lang[data-lang="CSS"] {
      color: var(--css-color);
    }
    .code-lang[data-lang="CPP"],
    .code-lang[data-lang="C"],
    .code-lang[data-lang="C++"] {
      color: var(--cpp-color);
    }

    .code-copy {
      position: absolute;
      top: 4px;
      right: 4px;
      border-radius: 999px;
      border: 1px solid var(--border);
      background: var(--bg-secondary);
      color: var(--text-secondary);
      font-size: 0.7rem;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      padding: 2px 8px;
      cursor: pointer;
      transition: 0.16s ease;
    }

    .code-copy svg {
      width: 12px;
      height: 12px;
      stroke: var(--text-muted);
    }

    .code-copy:hover {
      border-color: var(--accent-hover);
      color: var(--text-primary);
    }

    pre {
      margin-top: 8px;
      white-space: pre;
    }

    /* TYPING */

    .typing {
      display: none;
      margin: 0 16px 12px;
      padding: 8px 12px;
      border-radius: 999px;
      border: 1px dashed var(--border);
      background: var(--bg-secondary);
      font-size: 0.78rem;
      color: var(--text-muted);
      align-self: flex-start;
    }

    .typing.active {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      animation: fadePulse 1.4s infinite;
    }

    .typing-dots {
      display: inline-flex;
      gap: 3px;
    }

    .typing-dots span {
      width: 4px;
      height: 4px;
      border-radius: 999px;
      background: var(--text-muted);
      opacity: 0.4;
      animation: dotBlink 1s infinite;
    }

    .typing-dots span:nth-child(2) {
      animation-delay: 0.18s;
    }
    .typing-dots span:nth-child(3) {
      animation-delay: 0.36s;
    }

    /* INPUT */

    .input-area {
      border-top: 1px solid var(--border);
      padding: 10px 16px 12px;
      background: var(--bg-secondary);
    }

    .input-top {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: var(--text-xs);
      color: var(--text-muted);
      margin-bottom: 4px;
    }

    .input-main {
      display: flex;
      align-items: flex-end;
      gap: 8px;
    }

    .input-box {
      flex: 1;
      border-radius: 14px;
      border: 1px solid var(--border);
      background: var(--bg-primary);
      padding: 6px 10px;
      position: relative;
      box-shadow: 0 8px 26px var(--shadow);
    }

    .input-box textarea {
      width: 100%;
      border: none;
      outline: none;
      background: transparent;
      color: var(--text-primary);
      resize: none;
      max-height: 110px;
      min-height: 38px;
      font-size: var(--text-sm);
      line-height: 1.4;
    }

    .input-box textarea::placeholder {
      color: var(--text-muted);
    }

    .input-actions {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    .btn-main,
    .btn-regen {
      border-radius: 999px;
      border: 1px solid var(--border);
      padding: 7px 12px;
      min-width: 80px;
      font-size: var(--text-xs);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      cursor: pointer;
      transition: 0.16s ease;
      box-shadow: 0 8px 20px var(--shadow);
    }

    .btn-main svg,
    .btn-regen svg {
      width: 14px;
      height: 14px;
    }

    .btn-main {
      background: var(--gradient-3);
      color: var(--bg-primary);
    }

    .btn-main svg {
      stroke: var(--bg-primary);
    }

    .btn-main:hover {
      background: var(--gradient-4);
      transform: translateY(-1px);
    }

    .btn-regen {
      background: var(--bg-tertiary);
      color: var(--text-secondary);
    }

    .btn-regen svg {
      stroke: var(--text-muted);
    }

    .btn-regen:hover {
      background: var(--gradient-2);
      transform: translateY(-1px);
    }

    .btn-main:disabled,
    .btn-regen:disabled {
      opacity: 0.45;
      cursor: not-allowed;
      box-shadow: none;
      transform: none;
    }

    /* NAV DRAWER */

    .nav-backdrop {
      position: fixed;
      inset: 0;
      background: rgba(0, 0, 0, 0.65);
      opacity: 0;
      pointer-events: none;
      transition: 0.2s ease;
      z-index: 20;
    }

    .nav-backdrop.open {
      opacity: 1;
      pointer-events: auto;
    }

    .nav-drawer {
      position: fixed;
      top: 0;
      left: 0;
      width: 260px;
      height: 100%;
      background: var(--bg-secondary);
      border-right: 1px solid var(--border);
      box-shadow: 16px 0 40px var(--shadow);
      transform: translateX(-100%);
      transition: transform 0.22s ease-out;
      z-index: 30;
      display: flex;
      flex-direction: column;
    }

    .nav-drawer.open {
      transform: translateX(0);
    }

    .nav-header {
      padding: 12px 14px;
      border-bottom: 1px solid var(--border);
      display: flex;
      align-items: center;
      gap: 10px;
    }

    .nav-logo {
      width: 30px;
      height: 30px;
      border-radius: 999px;
      border: 1px solid var(--border);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 0.7rem;
      font-weight: 700;
      color: var(--text-primary);
      background: var(--bg-tertiary);
    }

    .nav-title-wrap {
      display: flex;
      flex-direction: column;
      gap: 2px;
    }

    .nav-title {
      font-size: 0.86rem;
      font-weight: 600;
      color: var(--text-primary);
    }

    .nav-sub {
      font-size: 0.72rem;
      color: var(--text-muted);
    }

    .nav-content {
      flex: 1;
      padding: 10px 14px 14px;
      overflow-y: auto;
      font-size: 0.78rem;
      color: var(--text-secondary);
      scrollbar-width: thin;
      scrollbar-color: var(--border) transparent;
    }

    .nav-section {
      margin-bottom: 12px;
    }

    .nav-section-title {
      font-size: 0.72rem;
      text-transform: uppercase;
      letter-spacing: 0.08em;
      color: var(--text-muted);
      margin-bottom: 6px;
    }

    .nav-button {
      width: 100%;
      padding: 7px 9px;
      border-radius: 9px;
      border: 1px solid var(--border);
      background: var(--bg-primary);
      color: var(--text-secondary);
      display: flex;
      align-items: center;
      justify-content: space-between;
      cursor: pointer;
      margin-bottom: 6px;
      transition: 0.16s ease;
    }

    .nav-button svg {
      width: 14px;
      height: 14px;
      stroke: var(--text-muted);
    }

    .nav-button:hover {
      border-color: #ff4d4d;
      color: #ffcccc;
      background: #1a0000;
    }

    .nav-field-label {
      margin-bottom: 4px;
      color: var(--text-secondary);
    }

    .nav-select,
    .nav-input {
      width: 100%;
      padding: 7px 9px;
      border-radius: 9px;
      border: 1px solid var(--border);
      background: var(--bg-primary);
      color: var(--text-primary);
      outline: none;
      font-size: 0.8rem;
    }

    .nav-input::placeholder {
      color: var(--text-muted);
    }

    .nav-save {
      margin-top: 6px;
      width: 100%;
      padding: 7px 9px;
      border-radius: 9px;
      border: 1px solid var(--border);
      background: var(--bg-tertiary);
      color: var(--text-secondary);
      font-size: 0.78rem;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      transition: 0.16s ease;
    }

    .nav-save svg {
      width: 13px;
      height: 13px;
      stroke: var(--text-muted);
    }

    .nav-save:hover {
      border-color: var(--accent-hover);
      color: var(--text-primary);
    }

    .nav-status {
      margin-top: 4px;
      font-size: 0.72rem;
    }

    /* TOAST */

    .toast {
      position: fixed;
      top: 20px;
      right: 20px;
      background: var(--bg-tertiary);
      border-radius: 999px;
      padding: 6px 12px;
      font-size: 0.78rem;
      color: var(--text-primary);
      display: inline-flex;
      align-items: center;
      gap: 6px;
      box-shadow: 0 12px 35px var(--shadow);
      border: 1px solid var(--border);
      opacity: 0;
      transform: translateY(-8px);
      pointer-events: none;
      transition: 0.2s ease;
      z-index: 40;
    }

    .toast svg {
      width: 14px;
      height: 14px;
      stroke: var(--accent-hover);
    }

    .toast.show {
      opacity: 1;
      transform: translateY(0);
    }

    /* ANIMATIONS */

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

    @keyframes fadePulse {
      0%,
      100% {
        opacity: 0.6;
      }
      50% {
        opacity: 1;
      }
    }

    @keyframes dotBlink {
      0%,
      100% {
        opacity: 0.3;
        transform: translateY(0);
      }
      50% {
        opacity: 1;
        transform: translateY(-1px);
      }
    }

    /* RESPONSIVE */

    @media (max-width: 768px) {
      .header,
      .quick-actions,
      .messages,
      .input-area {
        padding-inline: 12px;
      }
    }