:root {
    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', monospace;
    --r-sm: 8px; --r-md: 12px; --r-lg: 16px; --r-xl: 20px;
    --ease: cubic-bezier(0.4, 0, 0.2, 1);
}
[data-theme="dark"] {
    --bg: #0a0a0b; --bg-elevated: #121214; --bg-card: #18181b;
    --bg-hover: rgba(255,255,255,0.04); --bg-active: rgba(255,255,255,0.07);
    --bg-input: #18181b; --bg-overlay: rgba(0,0,0,0.7);
    --tx: #f5f5f5; --tx-secondary: #a1a1aa; --tx-tertiary: #52525b;
    --border: rgba(255,255,255,0.07); --border-strong: rgba(255,255,255,0.13);
    --accent: #5b6ef5; --accent-dim: rgba(91,110,245,0.1);
    --accent-hover: #4a5de0; --accent-glow: rgba(91,110,245,0.2);
    --green: #22c55e; --green-dim: rgba(34,197,94,0.1);
    --red: #ef4444; --red-dim: rgba(239,68,68,0.1);
    --shadow: 0 1px 3px rgba(0,0,0,0.3); --shadow-lg: 0 8px 32px rgba(0,0,0,0.5);
    --code-bg: #0d0d10; --code-border: rgba(255,255,255,0.05);
}
[data-theme="light"] {
    --bg: #fafafa; --bg-elevated: #ffffff; --bg-card: #ffffff;
    --bg-hover: rgba(0,0,0,0.03); --bg-active: rgba(0,0,0,0.06);
    --bg-input: #f3f3f6; --bg-overlay: rgba(0,0,0,0.3);
    --tx: #09090b; --tx-secondary: #71717a; --tx-tertiary: #a1a1aa;
    --border: rgba(0,0,0,0.07); --border-strong: rgba(0,0,0,0.13);
    --accent: #4f5ce5; --accent-dim: rgba(79,92,229,0.07);
    --accent-hover: #3e4bd0; --accent-glow: rgba(79,92,229,0.13);
    --green: #16a34a; --green-dim: rgba(22,163,74,0.07);
    --red: #dc2626; --red-dim: rgba(220,38,38,0.07);
    --shadow: 0 1px 3px rgba(0,0,0,0.05); --shadow-lg: 0 8px 24px rgba(0,0,0,0.08);
    --code-bg: #f5f5f7; --code-border: rgba(0,0,0,0.04);
}
*,*::before,*::after { margin:0; padding:0; box-sizing:border-box; }
html,body { height:100%; overflow:hidden; }
body {
    font-family:var(--font); background:var(--bg); color:var(--tx);
    -webkit-font-smoothing:antialiased; font-size:14px; line-height:1.5;
}
::selection { background:var(--accent-dim); color:var(--accent); }
::-webkit-scrollbar { width:4px; }
::-webkit-scrollbar-track { background:transparent; }
::-webkit-scrollbar-thumb { background:var(--tx-tertiary); border-radius:4px; }

#app { display:flex; height:100vh; }

/* ── SIDEBAR ── */
.sidebar {
    width:260px; min-width:260px; background:var(--bg-elevated);
    border-right:1px solid var(--border); display:flex; flex-direction:column; z-index:10;
}
.sidebar-header { padding:16px 16px 12px; display:flex; align-items:center; justify-content:space-between; }
.logo { display:flex; align-items:center; gap:10px; }
.logo-img { width:28px; height:28px; border-radius:6px; object-fit:cover; }
.logo-text { font-size:15px; font-weight:700; letter-spacing:-0.3px; color:var(--tx); }
.new-chat-btn {
    width:30px; height:30px; border-radius:var(--r-sm);
    border:1px solid var(--border); background:var(--bg-card); color:var(--tx-secondary);
    cursor:pointer; display:flex; align-items:center; justify-content:center; transition:all 0.15s var(--ease);
}
.new-chat-btn:hover { background:var(--bg-hover); color:var(--tx); border-color:var(--border-strong); }

.sidebar-search { padding:0 12px 10px; }
.search-box {
    display:flex; align-items:center; gap:6px; padding:7px 10px;
    background:var(--bg-card); border:1px solid var(--border); border-radius:var(--r-sm); transition:border-color 0.15s var(--ease);
}
.search-box:focus-within { border-color:var(--accent); box-shadow:0 0 0 2px var(--accent-dim); }
.search-box input { flex:1; background:none; border:none; outline:none; font-size:13px; color:var(--tx); font-family:var(--font); }
.search-box input::placeholder { color:var(--tx-tertiary); }

.conversations-list { flex:1; overflow-y:auto; padding:0 8px; }
.conversation-item {
    display:flex; align-items:center; gap:8px; padding:9px 10px;
    border-radius:var(--r-sm); cursor:pointer; transition:background 0.12s var(--ease);
    font-size:13px; color:var(--tx-secondary);
}
.conversation-item:hover { background:var(--bg-hover); color:var(--tx); }
.conversation-item.active { background:var(--accent-dim); color:var(--accent); }
.conversation-item .convo-title { flex:1; overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }
.conversation-item .convo-date { font-size:11px; color:var(--tx-tertiary); white-space:nowrap; }
.conversation-item .convo-del {
    width:22px; height:22px; border-radius:4px; border:none; background:transparent;
    color:var(--tx-tertiary); cursor:pointer; display:none; align-items:center;
    justify-content:center; flex-shrink:0; transition:all 0.1s var(--ease);
}
.conversation-item:hover .convo-del { display:flex; }
.conversation-item .convo-del:hover { background:var(--red-dim); color:var(--red); }
.empty-state { display:flex; flex-direction:column; align-items:center; justify-content:center; height:100px; color:var(--tx-tertiary); font-size:13px; gap:8px; }

.sidebar-footer { padding:12px; border-top:1px solid var(--border); }
.user-card {
    display:flex; align-items:center; gap:10px; padding:8px 10px;
    border-radius:var(--r-sm); background:var(--bg-card); border:1px solid var(--border);
    cursor:pointer; transition:background 0.12s var(--ease);
}
.user-card:hover { background:var(--bg-hover); }
.user-avatar {
    width:32px; height:32px; border-radius:50%; background:var(--bg-card);
    display:flex; align-items:center; justify-content:center; overflow:hidden;
    flex-shrink:0; border:1.5px solid var(--border);
}
.user-avatar img { width:100%; height:100%; object-fit:cover; }
.user-avatar-fallback { width:100%; height:100%; display:flex; align-items:center; justify-content:center; background:var(--accent-dim); color:var(--accent); font-size:13px; font-weight:600; }
.user-details { flex:1; min-width:0; }
.user-name { display:block; font-size:12px; font-weight:600; color:var(--tx); overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }
.user-email { display:block; font-size:10px; color:var(--tx-tertiary); overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }

.sidebar-actions { display:flex; gap:4px; margin-top:8px; }
.icon-btn {
    flex:1; height:30px; border-radius:var(--r-sm); border:1px solid var(--border);
    background:var(--bg-card); color:var(--tx-secondary); cursor:pointer;
    display:flex; align-items:center; justify-content:center; gap:4px;
    font-size:11px; font-family:var(--font); transition:all 0.12s var(--ease);
}
.icon-btn:hover { background:var(--bg-hover); color:var(--tx); border-color:var(--border-strong); }

[data-theme="dark"] .sun-icon { display:block; }
[data-theme="dark"] .moon-icon { display:none; }
[data-theme="light"] .sun-icon { display:none; }
[data-theme="light"] .moon-icon { display:block; }

/* ── MAIN ── */
.main-content { flex:1; display:flex; flex-direction:column; min-width:0; }
.chat-view { flex:1; display:flex; flex-direction:column; min-height:0; }
.chat-body { flex:1; display:flex; flex-direction:column; min-height:0; position:relative; }
.chat-messages { flex:1; overflow-y:auto; display:flex; flex-direction:column; }

/* ── WELCOME ── */
.welcome-screen {
    position:absolute; inset:0; display:flex; flex-direction:column;
    align-items:center; justify-content:center; padding:60px 24px;
    text-align:center; z-index:1; background:var(--bg);
}
.welcome-logo-img { width:56px; height:56px; border-radius:12px; margin-bottom:24px; }
.welcome-screen h1 { font-size:24px; font-weight:700; letter-spacing:-0.4px; color:var(--tx); margin-bottom:6px; }
.welcome-screen .subtitle { font-size:14px; color:var(--tx-secondary); margin-bottom:36px; max-width:420px; }
.quick-prompts { display:grid; grid-template-columns:repeat(3,1fr); gap:8px; max-width:600px; width:100%; }
.quick-prompt {
    display:flex; align-items:center; gap:8px; padding:12px 14px;
    border-radius:var(--r-md); border:1px solid var(--border); background:var(--bg-elevated);
    color:var(--tx-secondary); cursor:pointer; font-size:12px; font-family:var(--font);
    text-align:left; transition:all 0.12s var(--ease);
}
.quick-prompt:hover { background:var(--bg-card); border-color:var(--border-strong); color:var(--tx); box-shadow:var(--shadow); }
.quick-prompt svg { color:var(--tx-tertiary); flex-shrink:0; }
.quick-prompt:hover svg { color:var(--accent); }

/* ── MESSAGES ── */
.message { width:100%; max-width:760px; margin:0 auto; padding:24px 28px; display:flex; gap:14px; }
.message+.message { border-top:1px solid var(--border); }
.message-avatar {
    width:28px; height:28px; border-radius:6px; flex-shrink:0;
    display:flex; align-items:center; justify-content:center;
    overflow:hidden; margin-top:2px; font-size:11px; font-weight:600;
}
.message-avatar img { width:100%; height:100%; object-fit:cover; }
.message.user .message-avatar { background:var(--accent); color:white; }
.message.assistant .message-avatar { background:var(--accent); color:white; }
.message-body { flex:1; min-width:0; }
.message-content { font-size:14px; line-height:1.7; color:var(--tx); word-wrap:break-word; }
.message-content pre {
    background:var(--code-bg); border:1px solid var(--code-border);
    border-radius:var(--r-sm); padding:14px 16px; overflow-x:auto;
    margin:12px 0; font-size:12px; line-height:1.6; font-family:var(--mono);
}
.message-content code { font-family:var(--mono); background:var(--bg-card); padding:1px 5px; border-radius:4px; font-size:12px; }
.message-content pre code { background:none; padding:0; }
.message-content blockquote { border-left:3px solid var(--accent); padding:3px 0 3px 12px; margin:10px 0; color:var(--tx-secondary); }
.message-content table { border-collapse:collapse; width:100%; margin:10px 0; font-size:13px; }
.message-content th,.message-content td { border:1px solid var(--border); padding:6px 10px; text-align:left; }
.message-content th { background:var(--bg-card); font-weight:600; }
.message-actions { display:flex; gap:2px; margin-top:8px; opacity:0; transition:opacity 0.12s var(--ease); }
.message:hover .message-actions { opacity:1; }
.msg-action-btn {
    padding:4px 8px; border-radius:4px; border:1px solid var(--border);
    background:var(--bg-card); color:var(--tx-tertiary); cursor:pointer;
    font-size:11px; font-family:var(--font); display:flex; align-items:center;
    gap:4px; transition:all 0.1s var(--ease);
}
.msg-action-btn:hover { background:var(--bg-hover); color:var(--tx); border-color:var(--border-strong); }

/* ── CHAT INPUT ── */
.chat-input-area { flex-shrink:0; padding:0 28px 24px; display:flex; justify-content:center; }
.chat-input-wrapper {
    width:100%; max-width:760px; background:var(--bg-elevated);
    border:1px solid var(--border); border-radius:var(--r-lg);
    padding:12px 16px; transition:border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}
.chat-input-wrapper:focus-within { border-color:var(--accent); box-shadow:0 0 0 3px var(--accent-dim), var(--shadow); }
.rate-info { font-size:11px; color:var(--tx-tertiary); }
.input-row { display:flex; align-items:flex-end; gap:8px; }
.chat-input {
    flex:1; background:none; border:none; outline:none; resize:none;
    font-size:14px; font-family:var(--font); color:var(--tx);
    line-height:1.5; max-height:180px; min-height:22px;
}
.chat-input::placeholder { color:var(--tx-tertiary); }
.send-btn {
    width:32px; height:32px; border-radius:var(--r-sm); border:none;
    background:var(--accent); color:white; cursor:pointer; display:flex;
    align-items:center; justify-content:center; transition:all 0.12s var(--ease); flex-shrink:0;
}
.send-btn:hover { background:var(--accent-hover); box-shadow:0 2px 8px var(--accent-glow); }
.send-btn:disabled { opacity:0.25; cursor:not-allowed; box-shadow:none; }
.input-footer { margin-top:6px; font-size:10px; color:var(--tx-tertiary); text-align:center; }

/* ── LOGIN ── */
.login-card {
    background:var(--bg-elevated); border:1px solid var(--border);
    border-radius:var(--r-xl); padding:48px 40px; max-width:400px;
    width:100%; text-align:center; box-shadow:var(--shadow-lg);
}
.login-logo-img { width:56px; height:56px; border-radius:12px; margin:0 auto 20px; display:block; }
.login-card h2 { font-size:20px; font-weight:700; color:var(--tx); margin-bottom:6px; }
.login-card .login-desc { font-size:13px; color:var(--tx-secondary); margin-bottom:28px; line-height:1.5; }
.yandex-login-btn {
    display:inline-flex; align-items:center; gap:8px; padding:8px 24px;
    border-radius:var(--r-sm); border:1px solid var(--border); background:var(--bg-card); color:var(--tx);
    font-size:13px; font-weight:500; font-family:var(--font); cursor:pointer;
    transition:all 0.12s var(--ease);
}
.yandex-login-btn:hover { background:var(--bg-hover); border-color:var(--border-strong); }
.login-tariff-link {
    display:inline-flex; align-items:center; gap:4px; margin-top:12px;
    padding:5px 12px; border-radius:var(--r-sm); border:none;
    background:transparent; color:var(--tx-tertiary); font-size:12px;
    font-family:var(--font); cursor:pointer; transition:all 0.12s var(--ease);
}
.login-tariff-link:hover { color:var(--tx); }

/* ── MODAL ── */
.modal { position:fixed; inset:0; z-index:1000; display:flex; align-items:center; justify-content:center; }
.modal-overlay { position:absolute; inset:0; background:var(--bg-overlay); backdrop-filter:blur(4px); }
.modal-content {
    position:relative; background:var(--bg-elevated); border:1px solid var(--border);
    border-radius:var(--r-xl); box-shadow:var(--shadow-lg);
    max-width:880px; width:92%; max-height:85vh; overflow-y:auto; padding:28px;
}
.modal-header { display:flex; align-items:center; justify-content:space-between; margin-bottom:24px; }
.modal-header h2 { font-size:18px; font-weight:700; color:var(--tx); }
.modal-close {
    width:30px; height:30px; border-radius:var(--r-sm); border:1px solid var(--border);
    background:var(--bg-card); color:var(--tx-secondary); cursor:pointer;
    display:flex; align-items:center; justify-content:center; transition:all 0.1s var(--ease);
}
.modal-close:hover { background:var(--bg-hover); color:var(--tx); }

/* ── TARIFF CARDS ── */
.tariff-cards { display:grid; grid-template-columns:repeat(4,1fr); gap:10px; }
.tariff-card {
    background:var(--bg-card); border:1px solid var(--border);
    border-radius:var(--r-lg); padding:24px 18px; display:flex;
    flex-direction:column; position:relative; transition:all 0.15s var(--ease);
}
.tariff-card:hover { border-color:var(--border-strong); box-shadow:var(--shadow); transform:translateY(-1px); }
.tariff-card.popular { border-color:var(--accent); box-shadow:0 0 0 1px var(--accent), var(--shadow); }
.tariff-badge {
    position:absolute; top:-8px; left:50%; transform:translateX(-50%);
    background:var(--accent); color:white; font-size:9px; font-weight:700;
    padding:2px 10px; border-radius:20px; letter-spacing:0.3px; text-transform:uppercase;
}
.tariff-card h3 { font-size:14px; font-weight:700; color:var(--tx); margin-bottom:10px; }
.tariff-price { font-size:30px; font-weight:800; color:var(--tx); letter-spacing:-1px; line-height:1; }
.tariff-price span { font-size:12px; font-weight:500; color:var(--tx-secondary); }
.tariff-trial {
    display:inline-flex; align-items:center; gap:3px; margin-top:6px;
    padding:2px 8px; border-radius:20px; font-size:10px; font-weight:600;
    background:var(--green-dim); color:var(--green);
}
.tariff-features { list-style:none; margin:14px 0; flex:1; }
.tariff-features li {
    font-size:12px; color:var(--tx-secondary); padding:4px 0 4px 20px;
    position:relative; line-height:1.4;
}
.tariff-features li::before {
    content:''; position:absolute; left:0; top:7px; width:12px; height:12px;
    border-radius:50%; background:var(--accent-dim);
    background-image:url("data:image/svg+xml,%3Csvg width='8' height='8' viewBox='0 0 24 24' fill='none' stroke='%235b6ef5' stroke-width='4' xmlns='http://www.w3.org/2000/svg'%3E%3Cpolyline points='20 6 9 17 4 12'/%3E%3C/svg%3E");
    background-repeat:no-repeat; background-position:center;
}
.tariff-select-btn {
    width:100%; padding:9px; border-radius:var(--r-sm); border:1px solid var(--accent);
    background:transparent; color:var(--accent); font-size:12px; font-weight:600;
    font-family:var(--font); cursor:pointer; transition:all 0.12s var(--ease);
}
.tariff-select-btn:hover { background:var(--accent); color:white; box-shadow:0 2px 6px var(--accent-glow); }
.tariff-card.popular .tariff-select-btn { background:var(--accent); color:white; }
.tariff-card.popular .tariff-select-btn:hover { background:var(--accent-hover); }

/* ── PROFILE ── */
.profile-content { max-width:480px; margin:0 auto; text-align:center; }
.profile-avatar { width:72px; height:72px; border-radius:50%; margin:0 auto 16px; overflow:hidden; border:2px solid var(--border); }
.profile-avatar img { width:100%; height:100%; object-fit:cover; }
.profile-avatar .user-avatar-fallback { width:100%; height:100%; font-size:28px; }
.profile-name { font-size:18px; font-weight:700; color:var(--tx); margin-bottom:2px; }
.profile-email { font-size:13px; color:var(--tx-secondary); margin-bottom:20px; }
.profile-stats { display:grid; grid-template-columns:repeat(2,1fr); gap:8px; margin-bottom:20px; }
.profile-stat { background:var(--bg-card); border:1px solid var(--border); border-radius:var(--r-md); padding:14px; text-align:center; }
.profile-stat-value { font-size:22px; font-weight:800; color:var(--tx); line-height:1.2; }
.profile-stat-label { font-size:11px; color:var(--tx-tertiary); margin-top:2px; }
.profile-tariff {
    display:inline-flex; align-items:center; gap:6px; padding:6px 14px;
    background:var(--accent-dim); color:var(--accent); border-radius:var(--r-sm);
    font-size:12px; font-weight:600; margin-bottom:16px;
}

.confirm-content { max-width:360px; margin:0 auto; text-align:center; }
.confirm-content h3 { font-size:16px; font-weight:700; color:var(--tx); margin-bottom:8px; }
.confirm-content p { font-size:13px; color:var(--tx-secondary); margin-bottom:20px; }
.confirm-actions { display:flex; gap:8px; justify-content:center; }
.confirm-actions button { padding:9px 24px; border-radius:var(--r-sm); font-size:13px; font-weight:600; font-family:var(--font); cursor:pointer; transition:all 0.1s var(--ease); }
.confirm-cancel { border:1px solid var(--border); background:var(--bg-card); color:var(--tx-secondary); }
.confirm-cancel:hover { background:var(--bg-hover); color:var(--tx); border-color:var(--border-strong); }
.confirm-delete { border:none; background:var(--red); color:white; }
.confirm-delete:hover { background:#dc2626; box-shadow:0 2px 8px var(--red-dim); }

.typing-indicator { display:flex; gap:4px; padding:4px 0; }
.typing-indicator span { width:5px; height:5px; border-radius:50%; background:var(--accent); opacity:0.4; animation:tb 1.2s infinite ease-in-out; }
.typing-indicator span:nth-child(2) { animation-delay:0.15s; }
.typing-indicator span:nth-child(3) { animation-delay:0.3s; }
@keyframes tb { 0%,60%,100% { transform:translateY(0); opacity:0.4; } 30% { transform:translateY(-4px); opacity:1; } }

.notification {
    position:fixed; top:16px; right:16px; padding:12px 18px;
    border-radius:var(--r-md); background:var(--bg-elevated); border:1px solid var(--border);
    box-shadow:var(--shadow-lg); font-size:13px; color:var(--tx); z-index:2000;
    animation:ni 0.25s var(--ease); max-width:360px;
}
.notification.error { border-color:var(--red); background:var(--red-dim); color:var(--red); }
.notification.success { border-color:var(--green); background:var(--green-dim); color:var(--green); }
@keyframes ni { from { transform:translateY(-8px); opacity:0; } to { transform:translateY(0); opacity:1; } }

/* ── MOBILE ── */
.menu-toggle {
    display:none; position:fixed; top:12px; left:12px; z-index:50;
    width:36px; height:36px; border-radius:var(--r-sm); border:1px solid var(--border);
    background:var(--bg-elevated); color:var(--tx); cursor:pointer;
    align-items:center; justify-content:center; box-shadow:var(--shadow);
}
@media (max-width:900px) { .tariff-cards { grid-template-columns:repeat(2,1fr); } }
@media (max-width:768px) {
    .menu-toggle { display:flex; }
    .sidebar { position:fixed; left:-280px; top:0; bottom:0; z-index:100; transition:left 0.25s var(--ease); width:280px; min-width:280px; }
    .sidebar.open { left:0; box-shadow:var(--shadow-lg); }
    .quick-prompts { grid-template-columns:1fr; max-width:400px; }
    .chat-input-area { padding:0 12px 12px; }
    .chat-messages { padding-top:52px; }
    .message { padding:16px 12px; gap:10px; }
    .message-content { font-size:13px; }
    .chat-input-wrapper { padding:10px 12px; }
    .welcome-screen { padding:80px 16px 40px; }
    .welcome-logo-img { width:48px; height:48px; border-radius:10px; margin-bottom:16px; }
    .welcome-screen h1 { font-size:20px; }
    .modal-content { padding:20px; width:96%; }
    .login-card { padding:32px 24px; }
    .tariff-cards { grid-template-columns:1fr; gap:8px; }
}
@media (max-width:480px) {
    .sidebar-actions .icon-btn span { display:none; }
    .tariff-card { padding:18px 14px; }
    .tariff-price { font-size:26px; }
    .yandex-login-btn { padding:6px 16px; font-size:12px; }
}