/* ─── Design Tokens ─────────────────────────────────────────── */
:root {
    --bg:          #0d0d14;
    --bg-2:        #12121e;
    --bg-3:        #1a1a2e;
    --glass:       rgba(255,255,255,0.04);
    --glass-hover: rgba(255,255,255,0.07);
    --border:      rgba(255,255,255,0.08);
    --border-2:    rgba(255,255,255,0.14);

    --purple:      #7c3aed;
    --purple-2:    #a855f7;
    --cyan:        #06b6d4;
    --cyan-2:      #22d3ee;
    --green:       #10b981;
    --red:         #ef4444;

    --text:        #e2e8f0;
    --text-2:      #94a3b8;
    --text-3:      #64748b;

    --grad:        linear-gradient(135deg, #7c3aed 0%, #06b6d4 100%);
    --grad-soft:   linear-gradient(135deg, rgba(124,58,237,.15) 0%, rgba(6,182,212,.15) 100%);
    --glow:        0 0 24px rgba(124,58,237,.35), 0 0 48px rgba(6,182,212,.18);
    --glow-sm:     0 0 12px rgba(124,58,237,.25);

    --r:           16px;
    --r-sm:        10px;
    --r-xs:        6px;
    --transition:  0.2s ease;
    --font:        'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

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

/* ─── Base ──────────────────────────────────────────────────── */
html, body {
    height: 100%;
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    overflow: hidden;
}

/* Subtle grid background */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image:
        linear-gradient(rgba(124,58,237,.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(124,58,237,.04) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
    z-index: 0;
}

/* Ambient glow blobs */
body::after {
    content: '';
    position: fixed;
    top: -20%;
    left: -10%;
    width: 60%;
    height: 60%;
    background: radial-gradient(ellipse, rgba(124,58,237,.12) 0%, transparent 70%);
    pointer-events: none;
    z-index: 0;
}

/* ─── Layout ─────────────────────────────────────────────────── */
.header, .main, .input-footer { position: relative; z-index: 1; }

body {
    display: flex;
    flex-direction: column;
}

/* ─── Header ─────────────────────────────────────────────────── */
.header {
    flex-shrink: 0;
    height: 60px;
    background: rgba(13,13,20,.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
}

.header-brand {
    display: flex;
    align-items: center;
    gap: 12px;
}

.brand-logo {
    width: 34px;
    height: 34px;
    border-radius: 10px;
    background: var(--grad);
    box-shadow: var(--glow-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    color: #fff;
    font-weight: 700;
    flex-shrink: 0;
}

.brand-text {
    display: flex;
    flex-direction: column;
    gap: 1px;
}

.brand-name {
    font-size: 15px;
    font-weight: 700;
    background: var(--grad);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.3px;
}

.brand-sub {
    font-size: 11px;
    color: var(--text-3);
    font-weight: 400;
}

/* Video status pill */
.video-status {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--glass);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 6px 14px;
    font-size: 12px;
    color: var(--text-3);
    transition: var(--transition);
}

.video-status.active {
    border-color: rgba(16,185,129,.3);
    background: rgba(16,185,129,.06);
    color: var(--text-2);
}

.status-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--text-3);
    flex-shrink: 0;
    transition: var(--transition);
}

.video-status.active .status-dot {
    background: var(--green);
    box-shadow: 0 0 6px var(--green);
    animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
    0%, 100% { opacity: 1; }
    50%       { opacity: .5; }
}

/* ─── Main / Messages ─────────────────────────────────────────── */
.main {
    flex: 1;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.messages {
    flex: 1;
    overflow-y: auto;
    padding: 28px 20px 12px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    max-width: 800px;
    width: 100%;
    margin: 0 auto;
}

/* ─── Welcome Card ───────────────────────────────────────────── */
.welcome-card {
    margin: auto;
    padding: 40px 32px;
    background: var(--glass);
    border: 1px solid var(--border);
    border-radius: var(--r);
    backdrop-filter: blur(20px);
    text-align: center;
    max-width: 480px;
    width: 100%;
    animation: fadeUp .5s ease;
}

.welcome-icon {
    width: 56px;
    height: 56px;
    border-radius: 16px;
    background: var(--grad);
    box-shadow: var(--glow);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    color: #fff;
    margin: 0 auto 20px;
}

.welcome-card h2 {
    font-size: 22px;
    font-weight: 700;
    background: var(--grad);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.welcome-card p {
    font-size: 14px;
    color: var(--text-2);
    line-height: 1.6;
    margin-bottom: 24px;
}

.welcome-features {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: center;
}

.feature-chip {
    padding: 6px 14px;
    background: var(--grad-soft);
    border: 1px solid rgba(124,58,237,.25);
    border-radius: 20px;
    font-size: 12px;
    color: var(--text-2);
    font-weight: 500;
}

/* ─── Messages ───────────────────────────────────────────────── */
.message {
    display: flex;
    gap: 14px;
    padding: 14px 16px;
    border-radius: var(--r-sm);
    animation: fadeUp .25s ease;
    max-width: 100%;
}

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

/* User message */
.message.user {
    background: transparent;
    justify-content: flex-end;
    flex-direction: row-reverse;
}

.message.user .message-content {
    background: var(--grad-soft);
    border: 1px solid rgba(124,58,237,.25);
    border-radius: var(--r-sm) var(--r-xs) var(--r-sm) var(--r-sm);
    padding: 12px 16px;
    max-width: 75%;
    font-size: 14px;
    line-height: 1.6;
}

/* Bot message */
.message.bot {
    background: var(--glass);
    border: 1px solid var(--border);
    backdrop-filter: blur(10px);
}

.message.bot .message-content {
    font-size: 14px;
    line-height: 1.7;
    flex: 1;
    min-width: 0;
}

/* Avatars */
.message-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--r-xs);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    flex-shrink: 0;
    align-self: flex-start;
    margin-top: 2px;
}

.message.user .message-avatar {
    background: var(--grad);
    box-shadow: var(--glow-sm);
}

.message.bot .message-avatar {
    background: linear-gradient(135deg, #1a1a2e, #2d1b69);
    border: 1px solid rgba(124,58,237,.3);
}

/* ─── Typing Indicator ───────────────────────────────────────── */
.typing-indicator {
    display: inline-flex;
    gap: 5px;
    padding: 6px 2px;
    align-items: center;
}

.typing-indicator span {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--purple-2);
    animation: bounce 1.2s infinite ease-in-out;
}

.typing-indicator span:nth-child(2) { animation-delay: .2s; }
.typing-indicator span:nth-child(3) { animation-delay: .4s; }

@keyframes bounce {
    0%, 60%, 100% { transform: translateY(0); opacity: .6; }
    30%            { transform: translateY(-7px); opacity: 1; }
}

/* ─── Video Player ───────────────────────────────────────────── */
.video-player {
    margin: 12px 0;
    border-radius: var(--r-sm);
    overflow: hidden;
    border: 1px solid var(--border);
    box-shadow: var(--glow-sm);
}

.video-player iframe {
    width: 100%;
    height: 380px;
    border: none;
    display: block;
}

/* ─── Sources ────────────────────────────────────────────────── */
.sources {
    margin-top: 14px;
    padding: 14px;
    background: rgba(6,182,212,.05);
    border: 1px solid rgba(6,182,212,.15);
    border-radius: var(--r-sm);
}

.sources strong {
    display: block;
    margin-bottom: 10px;
    font-size: 12px;
    font-weight: 600;
    color: var(--cyan);
    text-transform: uppercase;
    letter-spacing: .6px;
}

.source-item {
    margin: 6px 0;
    padding: 8px 12px;
    background: var(--glass);
    border: 1px solid var(--border);
    border-radius: var(--r-xs);
    font-size: 12px;
    line-height: 1.5;
    color: var(--text-2);
}

.source-item strong {
    display: inline;
    color: var(--cyan);
    font-size: 11px;
    font-weight: 600;
    margin-right: 6px;
    text-transform: none;
    letter-spacing: 0;
}

/* ─── Loading ────────────────────────────────────────────────── */
.loading-message {
    color: var(--text-3);
    font-style: italic;
    font-size: 13px;
}

/* ─── Input Footer ───────────────────────────────────────────── */
.input-footer {
    flex-shrink: 0;
    padding: 16px 20px 20px;
    background: rgba(13,13,20,.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-top: 1px solid var(--border);
}

.input-shell {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

/* Quick action chips */
.quick-actions {
    display: none;
    gap: 8px;
    flex-wrap: wrap;
}

.quick-actions.visible {
    display: flex;
}

.action-chip {
    padding: 7px 16px;
    background: var(--glass);
    border: 1px solid var(--border);
    border-radius: 20px;
    color: var(--text-2);
    font-size: 13px;
    font-weight: 500;
    font-family: var(--font);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 6px;
}

.action-chip:hover {
    background: var(--grad-soft);
    border-color: rgba(124,58,237,.35);
    color: var(--text);
    transform: translateY(-1px);
}

.action-chip:disabled {
    opacity: .5;
    cursor: not-allowed;
    transform: none;
}

/* Input row */
.input-row {
    display: flex;
    align-items: center;
    gap: 10px;
    background: var(--bg-3);
    border: 1px solid var(--border);
    border-radius: var(--r-sm);
    padding: 10px 10px 10px 18px;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.input-row:focus-within {
    border-color: rgba(124,58,237,.5);
    box-shadow: 0 0 0 3px rgba(124,58,237,.08);
}

#user-input {
    flex: 1;
    background: transparent;
    border: none;
    outline: none;
    color: var(--text);
    font-size: 14px;
    font-family: var(--font);
    min-width: 0;
}

#user-input::placeholder { color: var(--text-3); }
#user-input:disabled    { opacity: .5; cursor: not-allowed; }

.send-btn {
    width: 36px;
    height: 36px;
    border-radius: var(--r-xs);
    background: var(--grad);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    flex-shrink: 0;
    transition: var(--transition);
    box-shadow: var(--glow-sm);
}

.send-btn:hover:not(:disabled) {
    box-shadow: var(--glow);
    transform: translateY(-1px);
}

.send-btn:disabled {
    opacity: .45;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.input-hint {
    font-size: 11px;
    color: var(--text-3);
    text-align: center;
}

/* ─── Study Materials Buttons (in-chat fallback) ─────────────── */
.study-materials-buttons {
    padding: 14px;
    background: rgba(124,58,237,.06);
    border: 1px solid rgba(124,58,237,.2);
    border-radius: var(--r-sm);
}

.study-materials-buttons p {
    font-size: 13px;
    color: var(--text-2);
    margin-bottom: 10px;
    font-weight: 500;
}

.study-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    margin: 4px 6px 4px 0;
    padding: 8px 16px;
    background: var(--glass);
    border: 1px solid rgba(124,58,237,.3);
    border-radius: 20px;
    color: var(--text-2);
    font-size: 13px;
    font-weight: 500;
    font-family: var(--font);
    cursor: pointer;
    transition: var(--transition);
}

.study-btn:hover {
    background: var(--grad-soft);
    border-color: rgba(124,58,237,.5);
    color: var(--text);
    transform: translateY(-1px);
}

/* ─── Scrollbar ───────────────────────────────────────────────── */
.messages::-webkit-scrollbar       { width: 6px; }
.messages::-webkit-scrollbar-track { background: transparent; }
.messages::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,.08);
    border-radius: 3px;
}
.messages::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,.14); }

/* ─── Markdown inside bot messages ───────────────────────────── */
.markdown-body h1, .markdown-body h2, .markdown-body h3 {
    margin: 16px 0 8px;
    font-weight: 600;
    line-height: 1.35;
    color: var(--text);
}
.markdown-body h1 { font-size: 1.15em; }
.markdown-body h2 { font-size: 1.05em; }
.markdown-body h3 { font-size: .97em; color: var(--text-2); }

.markdown-body p   { margin: 8px 0; line-height: 1.7; }
.markdown-body ul,
.markdown-body ol  { margin: 8px 0 8px 22px; }
.markdown-body li  { margin: 4px 0; line-height: 1.6; }

.markdown-body strong { color: #fff; font-weight: 600; }
.markdown-body em     { color: var(--text-2); }

.markdown-body code {
    background: rgba(124,58,237,.15);
    border: 1px solid rgba(124,58,237,.2);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: .85em;
    color: var(--purple-2);
}

.markdown-body pre {
    background: var(--bg-3);
    border: 1px solid var(--border);
    border-radius: var(--r-sm);
    padding: 14px;
    margin: 10px 0;
    overflow-x: auto;
}

.markdown-body pre code {
    background: none;
    border: none;
    padding: 0;
    color: var(--text-2);
    font-size: .88em;
}

.markdown-body hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 14px 0;
}

.markdown-body blockquote {
    border-left: 3px solid var(--purple);
    padding: 8px 14px;
    margin: 8px 0;
    color: var(--text-2);
    background: var(--glass);
    border-radius: 0 var(--r-xs) var(--r-xs) 0;
}

/* ─── Transcript Fallback Card ───────────────────────────────── */
.fallback-card {
    background: rgba(239,68,68,.06);
    border: 1px solid rgba(239,68,68,.25);
    border-radius: var(--r-sm);
    padding: 20px;
}

.fallback-title {
    font-size: 15px;
    font-weight: 600;
    color: #fca5a5;
    margin-bottom: 6px !important;
}

.fallback-sub {
    font-size: 13px;
    color: var(--text-2);
    margin-bottom: 14px !important;
}

.fallback-steps {
    margin: 0 0 16px 18px !important;
    font-size: 13px;
    color: var(--text-2);
    line-height: 1.8;
}

.fallback-steps strong { color: var(--text); }

.fallback-steps kbd {
    background: var(--bg-3);
    border: 1px solid var(--border-2);
    border-radius: 4px;
    padding: 1px 6px;
    font-size: 11px;
    font-family: monospace;
    color: var(--text);
}

.transcript-textarea {
    width: 100%;
    min-height: 130px;
    background: var(--bg-3);
    border: 1px solid var(--border);
    border-radius: var(--r-sm);
    color: var(--text);
    font-size: 13px;
    font-family: var(--font);
    padding: 12px;
    resize: vertical;
    outline: none;
    transition: border-color var(--transition);
    margin-bottom: 12px;
    display: block;
}

.transcript-textarea:focus { border-color: rgba(124,58,237,.5); }

.submit-transcript-btn {
    padding: 10px 24px;
    background: var(--grad);
    border: none;
    border-radius: var(--r-sm);
    color: #fff;
    font-size: 14px;
    font-weight: 600;
    font-family: var(--font);
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--glow-sm);
}

.submit-transcript-btn:hover:not(:disabled) {
    box-shadow: var(--glow);
    transform: translateY(-1px);
}

.submit-transcript-btn:disabled {
    opacity: .5;
    cursor: not-allowed;
    transform: none;
}

/* ─── Responsive ──────────────────────────────────────────────── */
@media (max-width: 640px) {
    .header { padding: 0 16px; }
    .brand-sub { display: none; }
    .messages { padding: 16px 12px 8px; }
    .input-footer { padding: 12px 12px 16px; }
    .video-player iframe { height: 220px; }
    .message.user .message-content { max-width: 90%; }
    .welcome-card { padding: 28px 20px; }
}