/* ─── Tokens ─────────────────────────────────────────────── */
:root {
    --blue-600:   #2563eb;
    --blue-700:   #1d4ed8;
    --blue-50:    #eff6ff;
    --slate-900:  #0f172a;
    --slate-800:  #1e293b;
    --slate-700:  #334155;
    --slate-500:  #64748b;
    --slate-300:  #cbd5e1;
    --slate-200:  #e2e8f0;
    --slate-100:  #f1f5f9;
    --slate-50:   #f8fafc;
    --white:      #ffffff;
    --danger:     #ef4444;

    --sidebar-w: 280px;
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 18px;

    --font-display: 'DM Serif Display', Georgia, serif;
    --font-body:    'DM Sans', system-ui, sans-serif;

    --shadow-sm: 0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
    --shadow-md: 0 4px 16px rgba(0,0,0,.08);
    --shadow-lg: 0 8px 32px rgba(0,0,0,.12);
}

/* ─── Reset & Base ───────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
    font-family: var(--font-body);
    font-size: 15px;
    color: var(--slate-800);
    background: var(--slate-100);
    height: 100dvh;
    overflow: hidden;
    display: flex;
}

/* ─── Layout ─────────────────────────────────────────────── */
.app-wrapper {
    display: flex;
    width: 100vw;
    height: 100dvh;
    overflow: hidden;
}

/* ─── Sidebar ────────────────────────────────────────────── */
.sidebar {
    width: var(--sidebar-w);
    background: var(--slate-900);
    color: var(--slate-300);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    height: 100dvh;
    transition: transform .3s cubic-bezier(.4,0,.2,1), width .3s cubic-bezier(.4,0,.2,1);
    overflow: hidden;
    z-index: 100;
}

/* Desktop: collapse sidebar by shrinking width */
.sidebar.hidden {
    width: 0;
    padding: 0;
    overflow: hidden;
}

/* Mobile: slide in as overlay */
@media (max-width: 700px) {
    .sidebar {
        position: fixed;
        left: 0; top: 0;
        transform: translateX(-100%);
    }
    .sidebar.hidden {
        width: var(--sidebar-w);
        transform: translateX(-100%);
    }
    .sidebar:not(.hidden) {
        transform: translateX(0);
        box-shadow: var(--shadow-lg);
    }
}

.sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 18px 16px;
    border-bottom: 1px solid rgba(255,255,255,.07);
}

.sidebar-logo {
    font-family: var(--font-display);
    font-size: 1.15rem;
    color: var(--white);
    letter-spacing: .02em;
}

.close-btn {
    background: transparent;
    border: none;
    color: var(--slate-500);
    font-size: 1rem;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: var(--radius-sm);
    transition: color .2s, background .2s;
}
.close-btn:hover { color: var(--white); background: rgba(255,255,255,.08); }

.sidebar-section {
    padding: 20px 18px 8px;
}

.sidebar-label {
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: .1em;
    text-transform: uppercase;
    color: var(--slate-500);
    margin-bottom: 10px;
}

.sidebar-action-btn {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 11px 14px;
    border-radius: var(--radius-md);
    border: none;
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: background .2s, color .2s;
}

.sidebar-action-btn.reset {
    background: rgba(255,255,255,.06);
    color: var(--slate-300);
}
.sidebar-action-btn.reset:hover {
    background: rgba(239,68,68,.15);
    color: #fca5a5;
}

.btn-icon { font-size: 1.1rem; }

.sidebar-info {
    background: rgba(255,255,255,.04);
    border-radius: var(--radius-md);
    padding: 12px 14px;
    border: 1px solid rgba(255,255,255,.06);
}
.sidebar-info p {
    font-size: 0.8rem;
    line-height: 1.6;
    color: var(--slate-500);
}

.sidebar-footer {
    margin-top: auto;
    padding: 16px 18px;
    font-size: 0.72rem;
    color: var(--slate-700);
    border-top: 1px solid rgba(255,255,255,.07);
    letter-spacing: .02em;
}

/* ─── Main Chat Container ────────────────────────────────── */
.chat-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 100dvh;
    overflow: hidden;
    background: var(--white);
}

/* ─── Topbar ─────────────────────────────────────────────── */
.topbar {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 24px;
    background: var(--white);
    border-bottom: 1px solid var(--slate-200);
    box-shadow: var(--shadow-sm);
    flex-shrink: 0;
    z-index: 10;
}

.menu-btn, .icon-btn {
    background: transparent;
    border: 1px solid var(--slate-200);
    border-radius: var(--radius-sm);
    color: var(--slate-500);
    font-size: 1rem;
    width: 36px;
    height: 36px;
    display: grid;
    place-items: center;
    cursor: pointer;
    transition: background .2s, color .2s, border-color .2s;
    flex-shrink: 0;
    padding: 0;
}
.menu-btn:hover, .icon-btn:hover {
    background: var(--slate-100);
    border-color: var(--slate-300);
    color: var(--slate-800);
}

.topbar-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: var(--font-display);
    font-size: 1.05rem;
    color: var(--slate-800);
    flex: 1;
}

.pulse-dot {
    width: 9px;
    height: 9px;
    background: #22c55e;
    border-radius: 50%;
    box-shadow: 0 0 0 3px rgba(34,197,94,.2);
    animation: pulse-ring 2s ease infinite;
    flex-shrink: 0;
}
@keyframes pulse-ring {
    0%   { box-shadow: 0 0 0 0 rgba(34,197,94,.4); }
    70%  { box-shadow: 0 0 0 6px rgba(34,197,94,0); }
    100% { box-shadow: 0 0 0 0 rgba(34,197,94,0); }
}

.topbar-actions { display: flex; gap: 8px; }

/* ─── Chat Box ───────────────────────────────────────────── */
.chat-box {
    flex: 1;
    overflow-y: auto;
    padding: 28px 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    scroll-behavior: smooth;
    background: var(--slate-50);
}

/* Custom scrollbar */
.chat-box::-webkit-scrollbar { width: 5px; }
.chat-box::-webkit-scrollbar-track { background: transparent; }
.chat-box::-webkit-scrollbar-thumb { background: var(--slate-300); border-radius: 99px; }

/* ─── Welcome Screen ─────────────────────────────────────── */
.welcome-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    margin: auto;
    padding: 40px 20px;
    max-width: 500px;
    animation: fadeUp .5s ease both;
}

.welcome-icon {
    font-size: 3rem;
    margin-bottom: 16px;
    filter: drop-shadow(0 4px 12px rgba(37,99,235,.3));
}

.welcome-screen h2 {
    font-family: var(--font-display);
    font-size: 1.8rem;
    color: var(--slate-800);
    margin-bottom: 10px;
}

.welcome-screen p {
    font-size: 0.9rem;
    color: var(--slate-500);
    line-height: 1.6;
    margin-bottom: 24px;
}

.suggestion-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: center;
}

.chip {
    background: var(--white);
    border: 1px solid var(--slate-200);
    border-radius: 99px;
    padding: 8px 16px;
    font-family: var(--font-body);
    font-size: 0.82rem;
    color: var(--slate-700);
    cursor: pointer;
    transition: border-color .2s, background .2s, color .2s, transform .15s;
    box-shadow: var(--shadow-sm);
}
.chip:hover {
    border-color: var(--blue-600);
    background: var(--blue-50);
    color: var(--blue-600);
    transform: translateY(-1px);
}

/* ─── Messages ───────────────────────────────────────────── */
.message {
    max-width: min(80%, 680px);
    padding: 13px 16px;
    border-radius: var(--radius-lg);
    line-height: 1.6;
    font-size: 0.915rem;
    animation: fadeUp .25s ease both;
    word-break: break-word;
}

.message.user {
    background: var(--blue-600);
    color: var(--white);
    margin-left: auto;
    border-bottom-right-radius: 4px;
    box-shadow: 0 2px 12px rgba(37,99,235,.25);
}

.message.assistant {
    background: var(--white);
    color: var(--slate-800);
    margin-right: auto;
    border-bottom-left-radius: 4px;
    border: 1px solid var(--slate-200);
    box-shadow: var(--shadow-sm);
}

/* Markdown content inside assistant messages */
.message.assistant p  { margin-bottom: 10px; }
.message.assistant p:last-child { margin-bottom: 0; }
.message.assistant ul, .message.assistant ol {
    padding-left: 20px;
    margin-bottom: 10px;
}
.message.assistant li { margin-bottom: 6px; }
.message.assistant strong { color: var(--slate-900); }

/* ─── Typing Indicator ───────────────────────────────────── */
.typing-indicator {
    display: flex;
    align-items: center;
    gap: 5px;
    padding: 14px 18px;
    width: 64px;
}

.typing-indicator span {
    display: block;
    width: 7px;
    height: 7px;
    background: var(--slate-400);
    border-radius: 50%;
    animation: blink 1.2s infinite both;
}
.typing-indicator span:nth-child(2) { animation-delay: .2s; }
.typing-indicator span:nth-child(3) { animation-delay: .4s; }

@keyframes blink {
    0%, 80%, 100% { transform: scale(.8); opacity: .5; }
    40%           { transform: scale(1.1); opacity: 1; }
}

/* ─── Input Area ─────────────────────────────────────────── */
.input-area {
    padding: 16px 24px 20px;
    background: var(--white);
    border-top: 1px solid var(--slate-200);
    flex-shrink: 0;
}

.input-wrapper {
    display: flex;
    align-items: center;
    gap: 10px;
    background: var(--slate-50);
    border: 1.5px solid var(--slate-200);
    border-radius: var(--radius-lg);
    padding: 8px 8px 8px 16px;
    transition: border-color .2s, box-shadow .2s;
}

.input-wrapper:focus-within {
    border-color: var(--blue-600);
    box-shadow: 0 0 0 3px rgba(37,99,235,.1);
}

.input-wrapper input {
    flex: 1;
    border: none;
    background: transparent;
    outline: none;
    font-family: var(--font-body);
    font-size: 0.93rem;
    color: var(--slate-800);
}

.input-wrapper input::placeholder { color: var(--slate-400); }

.send-btn {
    width: 38px;
    height: 38px;
    border-radius: 10px;
    background: var(--blue-600);
    color: var(--white);
    border: none;
    display: grid;
    place-items: center;
    cursor: pointer;
    flex-shrink: 0;
    transition: background .2s, transform .15s;
}
.send-btn:hover { background: var(--blue-700); transform: scale(1.05); }
.send-btn:active { transform: scale(.95); }

.input-disclaimer {
    margin-top: 8px;
    font-size: 0.72rem;
    color: var(--slate-400);
    text-align: center;
    line-height: 1.4;
}

/* ─── Animations ─────────────────────────────────────────── */
@keyframes fadeUp {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ─── Responsive ─────────────────────────────────────────── */
@media (max-width: 700px) {
    .chat-box { padding: 16px 12px; }
    .input-area { padding: 12px 12px 16px; }
    .topbar { padding: 12px 14px; }
    .topbar-title { font-size: 0.95rem; }
    .message { max-width: 95%; }
    .reset-top-btn { display: grid; } /* Always show on mobile */
}

@media (min-width: 701px) {
    .menu-btn { display: grid; }
}