:root {
  --bg-primary: #0F0F0F;
  --bg-secondary: #1C1C1E;
  --bg-tertiary: #2C2C2E;
  --bg-card: #1C1C1E;
  --bg-hover: #2C2C2E;
  --color-primary: #0088CC;
  --color-primary-light: #0099E5;
  --color-success: #34C759;
  --color-warning: #FF9500;
  --color-danger: #FF3B30;
  --text-primary: #FFFFFF;
  --text-secondary: #8E8E93;
  --text-tertiary: #636366;
  --border: #38383A;
  --radius: 10px;
  --radius-lg: 14px;
  --shadow: 0 2px 12px rgba(0,0,0,0.4);
  --header-height: 56px;
  --nav-height: 56px;
}

* { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body {
  width: 100%; height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  overflow-x: hidden;
}
a { text-decoration: none; color: inherit; }
button { border: none; background: none; color: inherit; font: inherit; cursor: pointer; }
input, textarea {
  border: none; outline: none; background: var(--bg-secondary);
  color: var(--text-primary); font: inherit;
  border-radius: var(--radius); padding: 12px 16px; width: 100%;
}
input::placeholder, textarea::placeholder { color: var(--text-tertiary); }

.app {
  max-width: 480px; margin: 0 auto; min-height: 100vh;
  background: var(--bg-primary); position: relative;
  padding-bottom: var(--nav-height);
}

.app-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(15,15,15,0.92);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  height: var(--header-height); display: flex; align-items: center;
  padding: 0 16px; border-bottom: 1px solid var(--border);
}
.app-header h1 { font-size: 17px; font-weight: 600; flex: 1; text-align: center; }
.app-header .btn-back {
  width: 36px; height: 36px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 20px; color: var(--color-primary); background: var(--bg-secondary);
}
.app-header .btn-action {
  width: 36px; height: 36px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; color: var(--color-primary); background: var(--bg-secondary);
}

.bottom-nav {
  position: fixed; bottom: 0; left: 50%; transform: translateX(-50%);
  width: 100%; max-width: 480px; height: var(--nav-height);
  background: rgba(28,28,30,0.95); backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px); border-top: 1px solid var(--border);
  display: flex; align-items: center; justify-content: space-around; z-index: 100;
}
.nav-item {
  display: flex; flex-direction: column; align-items: center;
  gap: 2px; color: var(--text-tertiary); font-size: 10px;
  padding: 6px 12px; border-radius: 8px; transition: 0.2s;
}
.nav-item.active { color: var(--color-primary); }
.nav-item .nav-icon { font-size: 22px; }

.chat-list { padding: 8px 0; }
.chat-item {
  display: flex; align-items: center; gap: 12px;
  padding: 10px 16px; cursor: pointer; transition: background 0.15s;
}
.chat-item:active { background: var(--bg-hover); }
.chat-avatar {
  width: 52px; height: 52px; border-radius: 50%; background: var(--bg-tertiary);
  flex-shrink: 0; display: flex; align-items: center; justify-content: center;
  font-size: 20px; overflow: hidden;
}
.chat-avatar img { width: 100%; height: 100%; object-fit: cover; }
.chat-info { flex: 1; min-width: 0; }
.chat-row { display: flex; align-items: center; justify-content: space-between; }
.chat-name { font-size: 15px; font-weight: 500; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.chat-time { font-size: 12px; color: var(--text-tertiary); flex-shrink: 0; }
.chat-preview { font-size: 13px; color: var(--text-secondary); margin-top: 2px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.chat-badge {
  min-width: 20px; height: 20px; border-radius: 10px; background: var(--color-primary);
  color: #fff; font-size: 12px; font-weight: 600;
  display: flex; align-items: center; justify-content: center;
  padding: 0 6px; margin-left: 8px;
}

.chat-room { display: flex; flex-direction: column; height: calc(100vh - var(--header-height)); }
.messages-container {
  flex: 1; overflow-y: auto; padding: 12px 16px;
  display: flex; flex-direction: column; gap: 4px;
}
.msg-bubble {
  max-width: 75%; padding: 10px 14px; border-radius: 18px;
  font-size: 14px; line-height: 1.45; word-break: break-word;
}
.msg-in { align-self: flex-start; background: var(--bg-tertiary); border-bottom-left-radius: 4px; color: var(--text-primary); }
.msg-out { align-self: flex-end; background: var(--color-primary); border-bottom-right-radius: 4px; color: #fff; }
.msg-time { font-size: 10px; opacity: 0.6; margin-top: 4px; text-align: right; }
.msg-in .msg-time { text-align: left; }

.input-area {
  display: flex; align-items: flex-end; gap: 8px;
  padding: 8px 12px; border-top: 1px solid var(--border); background: var(--bg-secondary);
}
.input-area textarea {
  flex: 1; resize: none; max-height: 120px;
  padding: 10px 14px; border-radius: 20px;
  background: var(--bg-tertiary); font-size: 15px;
}
.btn-send {
  width: 40px; height: 40px; border-radius: 50%;
  background: var(--color-primary); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; flex-shrink: 0;
}
.btn-send:active { opacity: 0.8; }

.settings-list { padding: 16px; }
.settings-group { margin-bottom: 24px; }
.settings-group-title {
  font-size: 13px; text-transform: uppercase;
  color: var(--text-secondary); padding: 0 12px; margin-bottom: 8px; letter-spacing: 0.5px;
}
.settings-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 16px; background: var(--bg-card);
  border-bottom: 1px solid var(--border); cursor: pointer;
}
.settings-item:first-child { border-radius: var(--radius) var(--radius) 0 0; }
.settings-item:last-child { border-radius: 0 0 var(--radius) var(--radius); border-bottom: none; }
.settings-item:only-child { border-radius: var(--radius); }
.settings-item:active { background: var(--bg-hover); }
.settings-item-left { display: flex; align-items: center; gap: 12px; }
.settings-item-icon { width: 28px; font-size: 18px; text-align: center; }
.settings-item-label { font-size: 15px; }
.settings-item-right { display: flex; align-items: center; gap: 8px; color: var(--text-tertiary); font-size: 14px; }

.toggle { width: 50px; height: 30px; border-radius: 15px; background: var(--bg-tertiary); position: relative; transition: 0.25s; flex-shrink: 0; }
.toggle::after { content: ''; position: absolute; width: 26px; height: 26px; border-radius: 50%; background: #fff; top: 2px; left: 2px; transition: 0.25s; }
.toggle.active { background: var(--color-success); }
.toggle.active::after { left: 22px; }

.login-container { display: flex; flex-direction: column; padding: 40px 24px; min-height: 100vh; }
.login-logo { text-align: center; margin-bottom: 40px; }
.logo-icon { font-size: 64px; margin-bottom: 8px; }
.login-logo h1 { font-size: 28px; font-weight: 700; margin-bottom: 4px; }
.login-logo p { color: var(--text-secondary); font-size: 15px; }
.login-form { display: flex; flex-direction: column; gap: 16px; }
.input-group label { display: block; font-size: 13px; color: var(--text-secondary); margin-bottom: 6px; }
.btn-primary {
  background: var(--color-primary); color: #fff; padding: 14px;
  border-radius: var(--radius); font-size: 16px; font-weight: 600;
  text-align: center; transition: opacity 0.2s;
}
.btn-primary:active { opacity: 0.85; }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-text { color: var(--color-primary); font-size: 14px; text-align: center; padding: 8px; }
.login-header { display: flex; align-items: center; gap: 12px; margin-bottom: 24px; }
.login-header h2 { font-size: 20px; font-weight: 600; }
.code-tip { text-align: center; color: var(--text-secondary); font-size: 14px; margin-bottom: 8px; }

.bind-content { flex: 1; }
.bind-info { text-align: center; margin-bottom: 20px; color: var(--text-secondary); font-size: 14px; }
.bind-box { background: var(--bg-card); border-radius: var(--radius-lg); padding: 20px; margin-bottom: 20px; }
.bind-code-section { text-align: center; margin-bottom: 20px; padding-bottom: 20px; border-bottom: 1px solid var(--border); }
.bind-label { font-size: 13px; color: var(--text-secondary); margin-bottom: 8px; }
.bind-code-display { font-size: 36px; font-weight: 700; letter-spacing: 8px; color: var(--color-primary); font-family: 'Courier New', monospace; }
.bind-countdown { font-size: 12px; color: var(--text-tertiary); margin-top: 6px; }
.bind-steps { display: flex; flex-direction: column; gap: 14px; }
.bind-step-item { display: flex; align-items: flex-start; gap: 12px; font-size: 14px; color: var(--text-secondary); line-height: 1.5; }
.step-num { width: 24px; height: 24px; border-radius: 50%; background: var(--color-primary); color: #fff; font-size: 12px; font-weight: 600; display: flex; align-items: center; justify-content: center; flex-shrink: 0; margin-top: 1px; }
.bind-actions { display: flex; flex-direction: column; gap: 10px; }
.bind-status { display: none; align-items: center; justify-content: center; gap: 8px; margin-top: 16px; font-size: 14px; color: var(--text-secondary); }
.spinner { width: 16px; height: 16px; border: 2px solid var(--text-tertiary); border-top-color: var(--color-primary); border-radius: 50%; animation: spin 0.8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

.profile-header { text-align: center; padding: 32px 16px; }
.profile-avatar { width: 90px; height: 90px; border-radius: 50%; background: var(--bg-tertiary); margin: 0 auto 12px; display: flex; align-items: center; justify-content: center; font-size: 36px; overflow: hidden; }
.profile-name { font-size: 20px; font-weight: 600; margin-bottom: 4px; }
.profile-username { font-size: 14px; color: var(--color-primary); }
.profile-actions { display: flex; gap: 12px; padding: 0 16px 20px; }
.profile-actions .btn-primary { flex: 1; }

.admin-container { padding: 16px; }
.admin-tabs { display: flex; gap: 4px; margin-bottom: 16px; overflow-x: auto; }
.admin-tab { padding: 8px 16px; border-radius: 8px; font-size: 14px; white-space: nowrap; color: var(--text-secondary); background: var(--bg-secondary); }
.admin-tab.active { background: var(--color-primary); color: #fff; }
.admin-section { display: none; }
.admin-section.active { display: block; }
.admin-form { display: flex; flex-direction: column; gap: 12px; }
.admin-form .input-group { display: flex; flex-direction: column; gap: 4px; }
.admin-form label { font-size: 13px; color: var(--text-secondary); }
.admin-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.admin-table th { text-align: left; padding: 10px 8px; color: var(--text-secondary); border-bottom: 1px solid var(--border); font-weight: 500; }
.admin-table td { padding: 10px 8px; border-bottom: 1px solid var(--border); }

.toast {
  position: fixed; top: 50%; left: 50%; transform: translate(-50%, -50%);
  background: rgba(0,0,0,0.88); color: #fff; padding: 12px 24px;
  border-radius: 8px; font-size: 14px; z-index: 9999;
  opacity: 0; pointer-events: none; transition: opacity 0.3s;
  text-align: center; max-width: 80%; word-break: break-word;
}
.toast.show { opacity: 1; }

.search-container { padding: 0 16px; }
.search-input-wrap { display: flex; align-items: center; gap: 8px; padding: 12px 0; }
.search-input-wrap input { flex: 1; background: var(--bg-tertiary); }

::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-thumb { background: var(--bg-tertiary); border-radius: 2px; }

.contacts-list { padding: 8px 0; }
.contact-item { display: flex; align-items: center; gap: 12px; padding: 10px 16px; cursor: pointer; }
.contact-item:active { background: var(--bg-hover); }
.contact-avatar { width: 44px; height: 44px; border-radius: 50%; background: var(--bg-tertiary); display: flex; align-items: center; justify-content: center; font-size: 18px; flex-shrink: 0; }
.contact-info { flex: 1; min-width: 0; }
.contact-name { font-size: 15px; font-weight: 500; }
.contact-status { font-size: 12px; color: var(--text-tertiary); margin-top: 2px; }