/* =====================================================
   AI CHAT PAGE - aicode.ptit.edu.vn Studio Edition
   ===================================================== */
.chat-page {
    overflow: hidden;
    background-color: var(--bg-layer-base);
}

.chat-layout {
    display: flex;
    height: calc(100vh - var(--header-h));
    background-image: radial-gradient(var(--dot-color) 1.2px, transparent 1.2px);
    background-size: 24px 24px;
}

/* ── Sidebar ─────────────────────────────────────────── */
.chat-sidebar {
    width: 290px;
    flex-shrink: 0;
    background: var(--surface-primary);
    border-right: 2px solid var(--border-primary);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.chat-sidebar-header {
    padding: 18px 20px;
    border-bottom: 2px solid var(--border-primary);
    background: linear-gradient(135deg, #181810 0%, #be123c 100%);
    color: #fff;
}

.chat-sidebar-title {
    font-size: 11px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--brand-primary);
    margin-bottom: 4px;
}

.chat-course-name {
    font-family: var(--font-brand);
    font-size: 14.5px;
    font-weight: 800;
    color: #fff;
    line-height: 1.4;
}

.chat-sidebar-back-wrap {
    padding: 12px 14px;
    border-bottom: 1.5px solid var(--border-secondary);
}

.btn-back-course {
    display: block;
    width: 100%;
    padding: 8px 12px;
    background: var(--surface-secondary);
    border: 1.5px solid var(--border-primary);
    box-shadow: 2px 2px 0px var(--border-primary);
    border-radius: var(--radius-sm);
    color: var(--text-label-1);
    font-size: 13px;
    font-weight: 700;
    text-align: center;
    text-decoration: none;
    transition: all var(--transition);
}

.btn-back-course:hover {
    background: var(--brand-primary);
    color: #fff;
    transform: translate(-1px, -1px);
    box-shadow: 3px 3px 0px var(--border-primary);
}

.chat-chapters-title {
    font-size: 11px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    color: var(--text-label-3);
    padding: 14px 16px 6px;
}

.chat-chapters {
    flex: 1;
    overflow-y: auto;
    padding: 10px;
}

/* Session card in chat sidebar */
.session-card {
    background: #ffffff;
    border: 2px solid var(--border-primary);
    box-shadow: 2.5px 2.5px 0px var(--border-primary);
    border-radius: 8px;
    padding: 12px 14px;
    margin-bottom: 10px;
    cursor: pointer;
    text-decoration: none;
    display: block;
    transition: all 0.15s ease;
}

.session-card:hover {
    transform: translate(-1px, -1px);
    box-shadow: 3.5px 3.5px 0px var(--border-primary);
    background: #f8fafc;
}

.session-card.active {
    background: var(--brand-primary, #ea580c) !important;
    color: #ffffff !important;
    border-color: var(--border-primary) !important;
    box-shadow: 3.5px 3.5px 0px var(--border-primary) !important;
    transform: translate(0, 0);
}

.session-chapter-tag {
    font-size: 10.5px;
    font-weight: 900;
    letter-spacing: 0.5px;
    color: var(--brand-primary, #ea580c);
    text-transform: uppercase;
}

.session-card.active .session-chapter-tag {
    color: #ffffff !important;
    opacity: 0.95;
}

.session-status-badge {
    font-size: 11px;
    font-weight: 800;
    padding: 2px 8px;
    border-radius: 4px;
    border: 1px solid var(--border-primary);
    display: inline-block;
    line-height: 1.2;
}

.session-status-badge.completed {
    background: #dcfce7;
    color: #15803d;
    border-color: #86efac;
}

.session-status-badge.in-progress {
    background: #fff7ed;
    color: #c2410c;
    border-color: #fed7aa;
}

[data-theme="dark"] .session-status-badge.in-progress {
    background: rgba(234, 88, 12, 0.22) !important;
    color: #fb923c !important;
    border-color: rgba(234, 88, 12, 0.5) !important;
}

[data-theme="dark"] .session-status-badge.completed {
    background: rgba(22, 163, 74, 0.22) !important;
    color: #4ade80 !important;
    border-color: rgba(22, 163, 74, 0.5) !important;
}

.session-card.active .session-status-badge.in-progress {
    background: rgba(0, 0, 0, 0.25) !important;
    color: #ffffff !important;
    border-color: rgba(255, 255, 255, 0.4) !important;
}

.session-card.active .session-status-badge.completed {
    background: #16a34a !important;
    color: #ffffff !important;
    border-color: #16a34a !important;
}

.session-title {
    font-family: var(--font);
    font-size: 13.5px;
    font-weight: 800;
    color: var(--text-label-1);
    line-height: 1.4;
}

.session-card.active .session-title {
    color: #ffffff !important;
}

[data-theme="dark"] .session-card:not(.active) .session-title {
    color: #ffffff !important;
}

/* ── Main Chat ───────────────────────────────────────── */
.chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: transparent;
    overflow: hidden;
}

.chat-header {
    background: var(--surface-primary);
    border-bottom: 2px solid var(--border-primary);
    padding: 14px 28px;
    display: flex;
    align-items: center;
    gap: 14px;
    flex-shrink: 0;
}

.chat-header-avatar {
    width: 40px;
    height: 40px;
    background: var(--brand-primary);
    border: 2px solid var(--border-primary);
    box-shadow: 2px 2px 0px var(--border-primary);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-weight: 900;
    font-size: 14px;
    flex-shrink: 0;
    position: relative;
}

.chat-header-avatar::after {
    content: '';
    position: absolute;
    bottom: -2px;
    right: -2px;
    width: 10px;
    height: 10px;
    background: var(--success);
    border-radius: 50%;
    border: 2px solid var(--border-primary);
}

.chat-header-info { flex: 1; }
.chat-header-name {
    font-family: var(--font-brand);
    font-size: 15.5px;
    font-weight: 800;
    color: var(--text-label-1);
}
.chat-header-sub {
    font-size: 12.5px;
    color: var(--text-label-3);
    display: flex;
    align-items: center;
    gap: 4px;
    margin-top: 2px;
}

.chat-online-dot {
    width: 8px;
    height: 8px;
    background: var(--success);
    border-radius: 50%;
    display: inline-block;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50%      { opacity: 0.5; transform: scale(0.85); }
}

/* ── Compact Exercise Bar ────────────────────────────── */
.compact-exercise-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 10px 28px;
    background: var(--surface-primary);
    border-bottom: 2px solid var(--border-primary);
    flex-shrink: 0;
}

.exercise-bar-info {
    display: flex;
    align-items: center;
    gap: 12px;
}

.exercise-bar-title {
    font-size: 13.5px;
    font-weight: 700;
    color: var(--text-label-1);
}

.exercise-bar-sub {
    font-size: 12px;
    color: var(--text-label-3);
}

.exercise-bar-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.exercise-status-badge {
    padding: 3px 10px;
    border-radius: var(--radius-sm);
    font-size: 11.5px;
    font-weight: 700;
    border: 1.5px solid var(--border-primary);
}

.exercise-status-badge.pending {
    background: #fff7ed;
    color: #c2410c;
}

.exercise-status-badge.completed {
    background: #f0fdf4;
    color: #15803d;
}

.btn-start-exercise-compact {
    display: inline-flex;
    align-items: center;
    padding: 6px 16px;
    background: var(--brand-primary);
    color: #fff;
    font-size: 12.5px;
    font-weight: 700;
    border-radius: var(--radius-sm);
    text-decoration: none;
    border: 1.5px solid var(--border-primary);
    box-shadow: 1.5px 1.5px 0px var(--border-primary);
    transition: all var(--transition);
}

.btn-start-exercise-compact:hover {
    background: var(--brand-primary-hover);
    transform: translate(-1px, -1px);
    box-shadow: 2.5px 2.5px 0px var(--border-primary);
}

/* ── Messages ────────────────────────────────────────── */
.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 24px 28px;
    display: flex;
    flex-direction: column;
    gap: 18px;
    scroll-behavior: smooth;
}

.msg-row {
    display: flex;
    gap: 10px;
    align-items: flex-end;
    animation: fadeUp 0.25s ease;
}

.msg-row.user {
    flex-direction: row-reverse;
}

.msg-avatar {
    width: 34px;
    height: 34px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 12px;
    flex-shrink: 0;
    border: 1.5px solid var(--border-primary);
}

.msg-avatar.ai {
    background: var(--brand-primary);
    color: #fff;
    box-shadow: 1.5px 1.5px 0px var(--border-primary);
}

.msg-avatar.user {
    background: var(--surface-primary);
    color: var(--text-label-1);
    box-shadow: 1.5px 1.5px 0px var(--border-primary);
}

.msg-bubble {
    max-width: 74%;
    padding: 14px 18px;
    border-radius: var(--radius-lg);
    font-size: 14.5px;
    line-height: 1.65;
    word-break: break-word;
    border: 2px solid var(--border-primary);
    box-shadow: var(--shadow-solid-sm);
}

.msg-row.ai .msg-bubble {
    background: var(--surface-primary);
    color: var(--text-label-1);
    border-bottom-left-radius: 2px;
}

.msg-row.user .msg-bubble {
    background: var(--brand-primary);
    color: #ffffff;
    border-bottom-right-radius: 2px;
}

.msg-time {
    font-size: 10.5px;
    color: var(--text-label-3);
    margin-top: 5px;
    text-align: right;
    font-weight: 600;
}
.msg-row.ai .msg-time { text-align: left; }

/* ── Typing Indicator ────────────────────────────────── */
.typing-indicator {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 12px 18px;
    background: var(--surface-primary);
    border: 2px solid var(--border-primary);
    border-radius: var(--radius-lg);
    border-bottom-left-radius: 2px;
    width: fit-content;
    box-shadow: var(--shadow-solid-sm);
}

.typing-dot {
    width: 8px;
    height: 8px;
    background: var(--text-label-3);
    border-radius: 50%;
    animation: typingBounce 1.4s ease infinite;
}
.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes typingBounce {
    0%, 60%, 100% { transform: translateY(0); background: var(--text-label-3); }
    30%           { transform: translateY(-6px); background: var(--brand-primary); }
}

/* ── Quick Suggestions ───────────────────────────────── */
.quick-suggestions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    padding: 0 28px 12px;
}

.suggestion-chip {
    padding: 6px 14px;
    background: var(--surface-primary);
    border: 1.5px solid var(--border-primary);
    box-shadow: 2px 2px 0px var(--border-primary);
    border-radius: var(--radius-sm);
    font-family: var(--font);
    font-size: 13px;
    font-weight: 700;
    color: var(--text-label-2);
    cursor: pointer;
    transition: all var(--transition);
    white-space: nowrap;
}

.suggestion-chip:hover {
    border-color: var(--brand-primary);
    color: var(--brand-primary);
    background: #fff7ed;
    transform: translate(-1px, -1px);
    box-shadow: 3px 3px 0px var(--border-primary);
}

/* ── Input Area ──────────────────────────────────────── */
.chat-input-area {
    padding: 14px 28px 18px;
    background: var(--surface-primary);
    border-top: 2px solid var(--border-primary);
    flex-shrink: 0;
}

.chat-input-form {
    display: flex;
    gap: 12px;
    align-items: center;
    background: #ffffff;
    border: 2.5px solid var(--border-primary);
    box-shadow: 4px 4px 0px var(--border-primary);
    border-radius: 12px;
    padding: 6px 8px 6px 16px;
    transition: all var(--transition);
}

.chat-input-form:focus-within {
    border-color: var(--brand-primary);
    box-shadow: 4px 4px 0px var(--brand-primary);
}

[data-theme="dark"] .chat-input-form {
    background: #0f172a !important;
    border: 2.5px solid #475569 !important;
    box-shadow: 4px 4px 0px #000000 !important;
}

[data-theme="dark"] .chat-input-form:focus-within {
    border-color: var(--brand-primary) !important;
    box-shadow: 4px 4px 0px var(--brand-primary) !important;
}

.chat-input-textarea {
    flex: 1;
    border: none !important;
    background: transparent !important;
    outline: none !important;
    font-family: var(--font);
    font-size: 14.5px;
    font-weight: 600;
    resize: none;
    min-height: 24px;
    max-height: 120px;
    line-height: 1.5;
    color: var(--text-label-1) !important;
    padding: 6px 0;
    box-shadow: none !important;
}

[data-theme="dark"] .chat-input-textarea {
    background: transparent !important;
    border: none !important;
    box-shadow: none !important;
    color: #ffffff !important;
}

[data-theme="dark"] .chat-input-textarea::placeholder {
    color: #94a3b8 !important;
}

.btn-send {
    padding: 8px 20px;
    height: 38px;
    background: var(--brand-primary);
    color: #fff;
    border: 2px solid var(--border-primary);
    box-shadow: 2px 2px 0px var(--border-primary);
    border-radius: var(--radius);
    font-family: var(--font);
    font-size: 13.5px;
    font-weight: 800;
    cursor: pointer;
    flex-shrink: 0;
    transition: all var(--transition);
}

.btn-send:hover {
    background: var(--brand-primary-hover);
    transform: translate(-1px, -1px);
    box-shadow: 3px 3px 0px var(--border-primary);
}

.btn-send:disabled {
    background: var(--border);
    color: var(--text-label-4);
    box-shadow: none;
    cursor: not-allowed;
    border-color: var(--border);
}

/* ── Math Toolbar ────────────────────────────────────── */
.math-toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 10px;
    padding: 6px 10px;
    background: var(--surface-secondary);
    border: 1.5px solid var(--border-primary);
    border-radius: var(--radius-sm);
}

.math-btn {
    padding: 4px 10px;
    font-family: var(--font-mono);
    font-size: 13px;
    font-weight: 700;
    color: var(--text-label-2);
    background: var(--surface-primary);
    border: 1.5px solid var(--border-primary);
    box-shadow: 1.5px 1.5px 0px var(--border-primary);
    border-radius: var(--radius-xs);
    cursor: pointer;
    transition: all var(--transition);
    user-select: none;
}

.math-btn:hover {
    color: #ffffff;
    background: var(--brand-primary);
    transform: translate(-1px, -1px);
    box-shadow: 2.5px 2.5px 0px var(--border-primary);
}

/* ── Markdown in AI Bubble ───────────────────────────── */
.msg-row.ai .msg-bubble.markdown-body pre {
    background: #181810;
    border: 2px solid var(--border-primary);
    box-shadow: 3px 3px 0px #000;
    border-radius: var(--radius);
    padding: 14px 18px;
    margin: 10px 0;
    overflow-x: auto;
}

.msg-row.ai .msg-bubble.markdown-body pre code {
    font-family: var(--font-mono);
    background: none;
    border: none;
    color: #f8fafc;
    font-size: 13px;
    padding: 0;
}

.msg-row.ai .msg-bubble.markdown-body code {
    font-family: var(--font-mono);
    font-size: 12.5px;
    background: #ffedd5;
    color: #c2410c;
    border: 1px solid var(--border-primary);
    border-radius: 4px;
    padding: 2px 6px;
    font-weight: 600;
}

/* Responsive */
@media (max-width: 768px) {
    .chat-sidebar { width: 220px; }
    .msg-bubble { max-width: 86%; }
    .chat-messages { padding: 16px; }
    .compact-exercise-bar { padding: 10px 16px; flex-direction: column; align-items: flex-start; }
}

@media (max-width: 600px) {
    .chat-sidebar { display: none; }
    .chat-layout { height: calc(100dvh - var(--header-h)); }
}