:root{
  --bg: #0A0A0B;
  --surface: #16161A;
  --surface-2: #1D1D22;
  --border: #2A2A30;
  --text: #F2F2F0;
  --text-dim: #94949C;
  --text-faint: #5C5C64;
  --accent: #7C6CFF;
  --accent-dim: #4A3FE0;
  --accent-soft: rgba(124,108,255,0.14);
  --danger: #FF6B6B;
  --radius-lg: 18px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --font-display: 'Space Grotesk', 'Inter', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

*{box-sizing:border-box; margin:0; padding:0;}
html,body{height:100%;}

/* 修正：hidden 屬性必須永遠優先於任何 display 設定，
   否則像 .modal-overlay / .control-group / .model-dropdown
   這種自帶 display:flex 的 class 會蓋掉 hidden，導致該隱藏的
   元素（設定視窗、模型選單、圖片/影片/Agent 參數列）一直顯示。 */
[hidden]{ display:none !important; }

body{
  background:var(--bg);
  color:var(--text);
  font-family:var(--font-body);
  font-size:15px;
  -webkit-font-smoothing:antialiased;
}
button{font-family:inherit; cursor:pointer; background:none; border:none; color:inherit;}
input,select,textarea{font-family:inherit; color:inherit;}
a{color:inherit; text-decoration:none;}

.app{
  display:flex;
  height:100vh;
  overflow:hidden;
}

/* ===== Sidebar ===== */
.sidebar{
  width:260px;
  flex-shrink:0;
  background:var(--surface);
  border-right:1px solid var(--border);
  display:flex;
  flex-direction:column;
  padding:16px 14px;
  transition:margin-left .25s ease;
}
.sidebar.collapsed{ margin-left:-260px; }

.sidebar-top{ display:flex; flex-direction:column; gap:16px; margin-bottom:22px; }
.brand{ display:flex; align-items:center; gap:8px; padding:4px 6px; }
.brand-mark{ color:var(--accent); font-size:16px; }
.brand-name{ font-family:var(--font-display); font-weight:600; font-size:17px; letter-spacing:-0.01em; }

.btn-new-chat{
  display:flex; align-items:center; gap:8px;
  padding:10px 12px;
  border:1px solid var(--border);
  border-radius:var(--radius-md);
  color:var(--text);
  font-size:13.5px; font-weight:500;
  transition:background .15s, border-color .15s;
}
.btn-new-chat:hover{ background:var(--surface-2); border-color:#3a3a42; }

.mode-list{ display:flex; flex-direction:column; gap:2px; flex:1; }
.mode-item{
  display:flex; align-items:center; gap:10px;
  padding:9px 10px;
  border-radius:var(--radius-sm);
  color:var(--text-dim);
  font-size:14px;
  transition:background .15s, color .15s;
  text-align:left;
}
.mode-item:hover{ background:var(--surface-2); color:var(--text); }
.mode-item.is-active{ background:var(--accent-soft); color:var(--accent); }
.mode-item svg{ flex-shrink:0; }

.sidebar-bottom{ display:flex; flex-direction:column; gap:8px; margin-top:12px; }

.settings-btn{
  display:flex; align-items:center; gap:10px;
  padding:9px 10px;
  border-radius:var(--radius-sm);
  color:var(--text-dim);
  font-size:13.5px;
  position:relative;
}
.settings-btn:hover{ background:var(--surface-2); color:var(--text); }
.key-dot{
  width:7px; height:7px; border-radius:50%;
  background:var(--text-faint);
  margin-left:auto;
}
.key-dot.is-set{ background:#3DD68C; box-shadow:0 0 6px rgba(61,214,140,.6); }

/* SuperbAPI badge */
.superbapi-badge{
  display:flex; align-items:center; gap:10px;
  padding:10px;
  border-radius:var(--radius-md);
  border:1px solid var(--border);
  background:linear-gradient(180deg, rgba(124,108,255,0.06), transparent);
  transition:border-color .15s, background .15s;
}
.superbapi-badge:hover{ border-color:var(--accent); background:var(--accent-soft); }
.superbapi-text{ display:flex; flex-direction:column; gap:1px; }
.superbapi-name{ font-size:12.5px; font-weight:600; color:var(--text); }
.superbapi-sub{ font-size:11px; color:var(--accent); }

/* ===== Main ===== */
.main{ flex:1; display:flex; flex-direction:column; min-width:0; }

.topbar{
  height:56px; flex-shrink:0;
  display:flex; align-items:center; gap:12px;
  padding:0 18px;
  border-bottom:1px solid var(--border);
}
.sidebar-toggle{ color:var(--text-dim); padding:6px; border-radius:var(--radius-sm); }
.sidebar-toggle:hover{ background:var(--surface-2); color:var(--text); }
.topbar-title{ font-family:var(--font-display); font-weight:600; font-size:15px; }
.model-picker{ position:relative; margin-left:8px; }
.model-picker-btn{
  display:flex; align-items:center; gap:6px;
  padding:6px 10px; border-radius:999px;
  border:1px solid var(--border); background:var(--surface-2);
  font-size:12.5px; color:var(--text-dim);
  max-width:220px;
}
.model-picker-btn:hover{ border-color:#454550; color:var(--text); }
.model-picker-btn span{ overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }
.model-picker-btn svg{ flex-shrink:0; color:var(--text-faint); }

.model-dropdown{
  position:absolute; top:calc(100% + 6px); left:0;
  width:280px; max-height:340px;
  background:var(--surface); border:1px solid var(--border);
  border-radius:var(--radius-md); box-shadow:0 12px 30px rgba(0,0,0,.4);
  display:flex; flex-direction:column; z-index:30; overflow:hidden;
}
.model-search{
  margin:8px; padding:8px 10px;
  background:var(--surface-2); border:1px solid var(--border);
  border-radius:var(--radius-sm); font-size:12.5px; outline:none;
}
.model-search:focus{ border-color:var(--accent); }
.model-options{ overflow-y:auto; padding:0 6px 8px; }
.model-option{
  display:flex; flex-direction:column;
  padding:8px 10px; border-radius:var(--radius-sm);
  font-size:12.5px; color:var(--text-dim); text-align:left; width:100%;
}
.model-option:hover{ background:var(--surface-2); color:var(--text); }
.model-option.is-selected{ background:var(--accent-soft); color:var(--accent); }
.model-option .model-owner{ font-size:10.5px; color:var(--text-faint); margin-top:1px; }
.model-empty{ padding:14px 10px; font-size:12px; color:var(--text-faint); line-height:1.6; text-align:center; }

.topbar-status{ margin-left:auto; display:flex; align-items:center; gap:7px; font-size:12.5px; color:var(--text-faint); }
.status-dot{ width:7px; height:7px; border-radius:50%; background:var(--text-faint); }
.status-dot.is-set{ background:#3DD68C; }

.chat-area{
  flex:1; overflow-y:auto;
  display:flex; flex-direction:column;
  padding:24px 0 12px;
}
.empty-state{
  margin:auto; text-align:center;
  max-width:420px; padding:0 20px;
  display:flex; flex-direction:column; align-items:center; gap:10px;
}
.empty-mark{ color:var(--accent); font-size:22px; margin-bottom:4px; }
.empty-state h1{ font-family:var(--font-display); font-size:22px; font-weight:600; }
.empty-state p{ color:var(--text-dim); font-size:14px; line-height:1.6; }

.messages{
  width:100%; max-width:760px; margin:0 auto;
  display:flex; flex-direction:column; gap:22px;
  padding:0 20px;
}
.msg{ display:flex; gap:12px; max-width:100%; }
.msg-user{ flex-direction:row-reverse; }
.msg-avatar{
  width:28px; height:28px; border-radius:8px; flex-shrink:0;
  display:flex; align-items:center; justify-content:center;
  font-size:12px; font-weight:600;
  background:var(--surface-2); color:var(--text-dim);
}
.msg-user .msg-avatar{ background:var(--accent-soft); color:var(--accent); }
.msg-body{ display:flex; flex-direction:column; gap:8px; max-width:80%; }
.msg-user .msg-body{ align-items:flex-end; }
.msg-bubble{
  padding:11px 14px; border-radius:var(--radius-md);
  background:var(--surface); border:1px solid var(--border);
  font-size:14.5px; line-height:1.65; white-space:pre-wrap; word-break:break-word;
}
.msg-user .msg-bubble{ background:var(--accent); color:#0A0A0B; border-color:var(--accent); font-weight:500; }
.msg-media{ border-radius:var(--radius-md); overflow:hidden; border:1px solid var(--border); max-width:340px; }
.msg-media img, .msg-media video{ display:block; width:100%; }
.msg-meta{ font-size:11px; color:var(--text-faint); }

/* ===== Composer ===== */
.composer{
  flex-shrink:0;
  padding:10px 20px 16px;
  max-width:820px; width:100%; margin:0 auto;
}
.composer-controls{ display:flex; flex-wrap:wrap; gap:16px; margin-bottom:10px; padding:0 4px; }
.control-group{ display:flex; align-items:center; gap:8px; flex-wrap:wrap; }
.control-label{ font-size:12px; color:var(--text-faint); margin-right:2px; }
.pill-group{ display:flex; gap:6px; }
.pill{
  padding:5px 11px; border-radius:999px;
  border:1px solid var(--border); color:var(--text-dim);
  font-size:12.5px; transition:all .15s;
}
.pill:hover{ border-color:#454550; color:var(--text); }
.pill.is-active{ background:var(--accent); border-color:var(--accent); color:#0A0A0B; font-weight:600; }

.agent-select{
  background:var(--surface-2); border:1px solid var(--border);
  border-radius:var(--radius-sm); padding:6px 10px; font-size:12.5px;
}
.agent-custom{
  background:var(--surface-2); border:1px solid var(--border);
  border-radius:var(--radius-sm); padding:6px 10px; font-size:12.5px;
  min-width:220px; flex:1;
}

.composer-bar{
  display:flex; align-items:flex-end; gap:8px;
  background:var(--surface);
  border:1px solid var(--border);
  border-radius:var(--radius-lg);
  padding:8px 8px 8px 10px;
}
.composer-bar:focus-within{ border-color:var(--accent); }

.upload-btn{
  width:34px; height:34px; border-radius:50%;
  display:flex; align-items:center; justify-content:center;
  color:var(--text-dim); border:1px solid var(--border);
  flex-shrink:0; transition:all .15s;
}
.upload-btn:hover{ color:var(--text); border-color:#454550; }

.input-wrap{ flex:1; display:flex; flex-direction:column; gap:6px; min-width:0; }
.attachments{ display:flex; flex-wrap:wrap; gap:6px; }
.attachment-chip{
  display:flex; align-items:center; gap:6px;
  background:var(--surface-2); border:1px solid var(--border);
  border-radius:999px; padding:4px 10px 4px 8px; font-size:11.5px; color:var(--text-dim);
}
.attachment-chip button{ color:var(--text-faint); font-size:13px; line-height:1; }

#promptInput{
  width:100%; resize:none; background:transparent; border:none; outline:none;
  color:var(--text); font-size:14.5px; line-height:1.5; max-height:160px; padding:6px 2px;
}
#promptInput::placeholder{ color:var(--text-faint); }

.send-btn{
  width:34px; height:34px; border-radius:50%; flex-shrink:0;
  display:flex; align-items:center; justify-content:center;
  background:var(--accent); color:#0A0A0B;
  transition:background .15s, opacity .15s;
}
.send-btn:hover{ background:#8f81ff; }
.send-btn:disabled{ opacity:.4; cursor:default; }

.composer-hint{ text-align:center; font-size:11px; color:var(--text-faint); margin-top:10px; }

/* ===== Modal ===== */
.modal-overlay{
  position:fixed; inset:0; background:rgba(0,0,0,.6);
  display:flex; align-items:center; justify-content:center; z-index:50;
  padding:20px;
}
.modal{
  width:100%; max-width:420px;
  background:var(--surface); border:1px solid var(--border);
  border-radius:var(--radius-lg);
  padding:22px;
}
.modal-head{ display:flex; align-items:center; justify-content:between; margin-bottom:18px; }
.modal-head h2{ font-family:var(--font-display); font-size:18px; font-weight:600; flex:1; }
.modal-close{ color:var(--text-faint); font-size:16px; }
.modal-close:hover{ color:var(--text); }

.field-label{ display:block; font-size:12.5px; color:var(--text-dim); margin-bottom:6px; }
.key-input-row{ display:flex; gap:8px; margin-bottom:14px; }
#apiKeyInput{
  flex:1; background:var(--surface-2); border:1px solid var(--border);
  border-radius:var(--radius-sm); padding:10px 12px; font-size:13.5px; outline:none;
}
#apiKeyInput:focus{ border-color:var(--accent); }

.ghost-btn{
  padding:9px 14px; border-radius:var(--radius-sm);
  border:1px solid var(--border); color:var(--text-dim); font-size:12.5px; font-weight:500;
  white-space:nowrap;
}
.ghost-btn:hover{ border-color:#454550; color:var(--text); }

.security-note{
  display:flex; gap:9px; padding:12px; border-radius:var(--radius-md);
  background:var(--accent-soft); border:1px solid rgba(124,108,255,.25);
  margin-bottom:16px;
}
.security-note svg{ flex-shrink:0; color:var(--accent); margin-top:1px; }
.security-note p{ font-size:12px; line-height:1.6; color:#C9C4FF; }

.modal-actions{ display:flex; gap:8px; }
.primary-btn{
  flex:1; padding:10px 14px; border-radius:var(--radius-sm);
  background:var(--accent); color:#0A0A0B; font-size:13.5px; font-weight:600;
  text-align:center; transition:background .15s;
}
.primary-btn:hover{ background:#8f81ff; }

.divider{ height:1px; background:var(--border); margin:18px 0; }

.no-key-cta{ text-align:center; }
.no-key-cta p{ font-size:12.5px; color:var(--text-dim); margin-bottom:10px; }
.cta-link{ display:block; }

/* ===== Scrollbar ===== */
.chat-area::-webkit-scrollbar{ width:8px; }
.chat-area::-webkit-scrollbar-thumb{ background:var(--border); border-radius:8px; }

/* ===== Responsive ===== */
@media (max-width:760px){
  .sidebar{ position:fixed; z-index:40; height:100%; margin-left:-260px; box-shadow:0 0 30px rgba(0,0,0,.4); }
  .sidebar.is-open{ margin-left:0; }
  .messages{ padding:0 12px; }
  .composer{ padding:10px 12px 14px; }
}

@media (prefers-reduced-motion: reduce){
  *{ transition:none !important; animation:none !important; }
}