/* ============================================
   Nova AI Chat Bot — Design System & Styles
   ============================================ */

/* --- CSS Variables (Design Tokens) --- */
:root {
    /* Primary Palette */
    --primary-hue: 250;
    --primary: hsl(var(--primary-hue), 80%, 60%);
    --primary-light: hsl(var(--primary-hue), 80%, 72%);
    --primary-dark: hsl(var(--primary-hue), 80%, 48%);
    --primary-glow: hsla(var(--primary-hue), 80%, 60%, 0.3);

    /* Accent */
    --accent: hsl(170, 70%, 50%);
    --accent-glow: hsla(170, 70%, 50%, 0.25);

    /* Dark Theme (Default) */
    --bg-primary: hsl(225, 25%, 8%);
    --bg-secondary: hsl(225, 25%, 11%);
    --bg-elevated: hsl(225, 20%, 14%);
    --bg-glass: hsla(225, 25%, 14%, 0.65);
    --bg-input: hsl(225, 20%, 12%);
    --border-color: hsla(225, 20%, 30%, 0.35);
    --border-subtle: hsla(225, 20%, 25%, 0.2);

    --text-primary: hsl(0, 0%, 95%);
    --text-secondary: hsl(225, 10%, 65%);
    --text-muted: hsl(225, 10%, 45%);

    /* Message Bubbles */
    --msg-user-bg: linear-gradient(135deg, hsl(var(--primary-hue), 70%, 50%), hsl(var(--primary-hue), 85%, 40%));
    --msg-user-text: #ffffff;
    --msg-bot-bg: var(--bg-elevated);
    --msg-bot-text: var(--text-primary);

    /* Surfaces */
    --surface-hover: hsla(var(--primary-hue), 50%, 60%, 0.08);
    --danger: hsl(0, 75%, 55%);
    --success: hsl(145, 65%, 45%);

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-xs: 0.7rem;
    --font-size-sm: 0.8rem;
    --font-size-base: 0.9rem;
    --font-size-lg: 1.05rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;

    /* Spacing */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 18px;
    --radius-xl: 24px;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 2px 8px hsla(0, 0%, 0%, 0.15);
    --shadow-md: 0 4px 20px hsla(0, 0%, 0%, 0.25);
    --shadow-lg: 0 8px 40px hsla(0, 0%, 0%, 0.35);
    --shadow-glow: 0 0 30px var(--primary-glow);

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- Light Theme --- */
[data-theme="light"] {
    --bg-primary: hsl(225, 25%, 95%);
    --bg-secondary: hsl(225, 20%, 98%);
    --bg-elevated: hsl(0, 0%, 100%);
    --bg-glass: hsla(0, 0%, 100%, 0.7);
    --bg-input: hsl(225, 20%, 96%);
    --border-color: hsla(225, 20%, 70%, 0.3);
    --border-subtle: hsla(225, 20%, 70%, 0.15);

    --text-primary: hsl(225, 30%, 15%);
    --text-secondary: hsl(225, 15%, 45%);
    --text-muted: hsl(225, 10%, 60%);

    --msg-bot-bg: hsl(0, 0%, 100%);
    --msg-bot-text: var(--text-primary);

    --surface-hover: hsla(var(--primary-hue), 50%, 60%, 0.06);

    --shadow-sm: 0 2px 8px hsla(225, 30%, 50%, 0.08);
    --shadow-md: 0 4px 20px hsla(225, 30%, 50%, 0.12);
    --shadow-lg: 0 8px 40px hsla(225, 30%, 50%, 0.15);
}

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 16px;
    transition: background var(--transition-base), color var(--transition-base);
    overflow: hidden;
}

/* --- Animated Background Orbs --- */
.bg-orbs {
    position: fixed;
    inset: 0;
    overflow: hidden;
    pointer-events: none;
    z-index: 0;
}

.orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.35;
    animation: orbit 20s infinite ease-in-out;
}

.orb-1 {
    width: 400px;
    height: 400px;
    background: hsl(var(--primary-hue), 80%, 55%);
    top: -100px;
    right: -100px;
    animation-duration: 22s;
}

.orb-2 {
    width: 300px;
    height: 300px;
    background: hsl(170, 70%, 45%);
    bottom: -80px;
    left: -80px;
    animation-duration: 18s;
    animation-delay: -5s;
}

.orb-3 {
    width: 250px;
    height: 250px;
    background: hsl(300, 60%, 50%);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation-duration: 25s;
    animation-delay: -10s;
}

[data-theme="light"] .orb {
    opacity: 0.15;
}

@keyframes orbit {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(40px, -30px) scale(1.05); }
    50% { transform: translate(-20px, 50px) scale(0.95); }
    75% { transform: translate(-40px, -20px) scale(1.02); }
}

/* --- Chat Container --- */
.chat-container {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 800px;
    height: calc(100vh - 32px);
    max-height: 900px;
    display: flex;
    flex-direction: column;
    background: var(--bg-glass);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    transition: background var(--transition-base), border-color var(--transition-base);
}

/* --- Header --- */
.chat-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    background: var(--bg-glass);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-subtle);
    flex-shrink: 0;
}

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

.bot-avatar {
    width: 42px;
    height: 42px;
    border-radius: var(--radius-md);
    background: var(--msg-user-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    box-shadow: var(--shadow-glow);
    animation: pulse-glow 3s ease-in-out infinite;
}

@keyframes pulse-glow {
    0%, 100% { box-shadow: 0 0 15px var(--primary-glow); }
    50% { box-shadow: 0 0 30px var(--primary-glow), 0 0 60px hsla(var(--primary-hue), 80%, 60%, 0.15); }
}

.header-info h1 {
    font-size: var(--font-size-lg);
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--text-primary), var(--primary-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.status-indicator {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: var(--font-size-xs);
    color: var(--text-muted);
    font-weight: 500;
}

.status-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--success);
    box-shadow: 0 0 8px hsla(145, 65%, 45%, 0.5);
    animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.header-actions {
    display: flex;
    gap: 4px;
}

.header-btn {
    width: 38px;
    height: 38px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.header-btn:hover {
    background: var(--surface-hover);
    color: var(--primary);
    transform: scale(1.05);
}

/* --- Messages Area --- */
.chat-messages {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    scroll-behavior: smooth;
}

/* Custom Scrollbar */
.chat-messages::-webkit-scrollbar {
    width: 5px;
}

.chat-messages::-webkit-scrollbar-track {
    background: transparent;
}

.chat-messages::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: var(--radius-full);
}

.chat-messages::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* --- Welcome Screen --- */
.welcome-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    flex: 1;
    text-align: center;
    gap: 16px;
    padding: 40px 20px;
    animation: fadeInUp 0.6s ease-out;
}

.welcome-icon {
    width: 80px;
    height: 80px;
    border-radius: var(--radius-lg);
    background: var(--msg-user-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    box-shadow: var(--shadow-glow);
    margin-bottom: 8px;
}

.welcome-screen h2 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, var(--text-primary), var(--primary-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-screen p {
    color: var(--text-secondary);
    font-size: var(--font-size-base);
    max-width: 360px;
    line-height: 1.6;
}

.quick-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    margin-top: 12px;
    width: 100%;
    max-width: 440px;
}

.quick-action-btn {
    padding: 12px 14px;
    background: var(--bg-elevated);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-family: var(--font-family);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-align: left;
}

.quick-action-btn:hover {
    border-color: var(--primary);
    color: var(--primary-light);
    background: var(--surface-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

/* --- Message Bubbles --- */
.message-row {
    display: flex;
    gap: 10px;
    max-width: 85%;
    animation: fadeInUp 0.35s ease-out;
}

.message-row.user {
    align-self: flex-end;
    flex-direction: row-reverse;
}

.message-row.bot {
    align-self: flex-start;
}

.message-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    font-size: var(--font-size-sm);
    font-weight: 600;
    margin-top: 2px;
}

.message-row.bot .message-avatar {
    background: var(--msg-user-bg);
    color: #fff;
}

.message-row.user .message-avatar {
    background: var(--bg-elevated);
    color: var(--primary-light);
    border: 1px solid var(--border-subtle);
}

.message-content {
    padding: 12px 16px;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    line-height: 1.65;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.message-row.user .message-content {
    background: var(--msg-user-bg);
    color: var(--msg-user-text);
    border-bottom-right-radius: var(--radius-sm);
}

.message-row.bot .message-content {
    background: var(--msg-bot-bg);
    color: var(--msg-bot-text);
    border: 1px solid var(--border-subtle);
    border-bottom-left-radius: var(--radius-sm);
}

/* Markdown Content Styles */
.message-row.bot .message-content h1,
.message-row.bot .message-content h2,
.message-row.bot .message-content h3 {
    margin: 12px 0 6px;
    font-weight: 600;
}

.message-row.bot .message-content h1 { font-size: 1.15rem; }
.message-row.bot .message-content h2 { font-size: 1.05rem; }
.message-row.bot .message-content h3 { font-size: 0.95rem; }

.message-row.bot .message-content p {
    margin-bottom: 8px;
}

.message-row.bot .message-content p:last-child {
    margin-bottom: 0;
}

.message-row.bot .message-content ul,
.message-row.bot .message-content ol {
    margin: 6px 0;
    padding-left: 20px;
}

.message-row.bot .message-content li {
    margin-bottom: 4px;
}

.message-row.bot .message-content code {
    background: hsla(var(--primary-hue), 40%, 50%, 0.12);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.85em;
    font-family: 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
}

.message-row.bot .message-content pre {
    background: hsla(0, 0%, 0%, 0.3);
    border-radius: var(--radius-sm);
    padding: 12px 14px;
    margin: 8px 0;
    overflow-x: auto;
    border: 1px solid var(--border-subtle);
}

[data-theme="light"] .message-row.bot .message-content pre {
    background: hsl(225, 20%, 96%);
}

.message-row.bot .message-content pre code {
    background: none;
    padding: 0;
    font-size: 0.82em;
    line-height: 1.5;
}

.message-row.bot .message-content strong {
    font-weight: 600;
    color: var(--primary-light);
}

[data-theme="light"] .message-row.bot .message-content strong {
    color: var(--primary-dark);
}

.message-row.bot .message-content a {
    color: var(--primary-light);
    text-decoration: underline;
    text-underline-offset: 2px;
}

.message-row.bot .message-content blockquote {
    border-left: 3px solid var(--primary);
    padding-left: 12px;
    margin: 8px 0;
    color: var(--text-secondary);
    font-style: italic;
}

.message-timestamp {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
    margin-top: 4px;
    padding: 0 4px;
}

.message-row.user .message-timestamp {
    text-align: right;
}

/* --- Typing Indicator --- */
.typing-indicator {
    display: flex;
    gap: 10px;
    align-self: flex-start;
    max-width: 85%;
    animation: fadeInUp 0.3s ease-out;
}

.typing-indicator .message-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm);
    background: var(--msg-user-bg);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    font-size: var(--font-size-sm);
    font-weight: 600;
}

.typing-dots {
    display: flex;
    align-items: center;
    gap: 5px;
    padding: 14px 18px;
    background: var(--msg-bot-bg);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    border-bottom-left-radius: var(--radius-sm);
}

.typing-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--text-muted);
    animation: typingBounce 1.4s ease-in-out infinite;
}

.typing-dot:nth-child(2) { animation-delay: 0.15s; }
.typing-dot:nth-child(3) { animation-delay: 0.3s; }

@keyframes typingBounce {
    0%, 60%, 100% { transform: translateY(0); opacity: 0.4; }
    30% { transform: translateY(-6px); opacity: 1; }
}

/* --- Input Area --- */
.chat-input-area {
    padding: 16px 20px;
    background: var(--bg-glass);
    backdrop-filter: blur(12px);
    border-top: 1px solid var(--border-subtle);
    flex-shrink: 0;
}

.input-wrapper {
    display: flex;
    align-items: flex-end;
    gap: 10px;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 6px 6px 6px 16px;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.input-wrapper:focus-within {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-glow);
}

.input-wrapper textarea {
    flex: 1;
    border: none;
    outline: none;
    background: transparent;
    color: var(--text-primary);
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.5;
    resize: none;
    max-height: 120px;
    padding: 8px 0;
}

.input-wrapper textarea::placeholder {
    color: var(--text-muted);
}

.send-btn {
    width: 40px;
    height: 40px;
    border: none;
    border-radius: var(--radius-md);
    background: var(--msg-user-bg);
    color: #fff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all var(--transition-fast);
    opacity: 0.5;
    pointer-events: none;
}

.send-btn.active {
    opacity: 1;
    pointer-events: all;
}

.send-btn.active:hover {
    transform: scale(1.08);
    box-shadow: var(--shadow-glow);
}

.send-btn.active:active {
    transform: scale(0.95);
}

.input-info {
    display: flex;
    justify-content: space-between;
    padding: 6px 4px 0;
    font-size: var(--font-size-xs);
    color: var(--text-muted);
}

/* --- Error Message --- */
.error-message {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 14px;
    background: hsla(0, 75%, 55%, 0.1);
    border: 1px solid hsla(0, 75%, 55%, 0.25);
    border-radius: var(--radius-md);
    color: var(--danger);
    font-size: var(--font-size-sm);
    animation: fadeInUp 0.3s ease-out;
    max-width: 85%;
    align-self: center;
}

.error-message svg {
    flex-shrink: 0;
}

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

/* --- Responsive --- */
@media (max-width: 640px) {
    body {
        padding: 0;
    }

    .chat-container {
        height: 100vh;
        max-height: none;
        border-radius: 0;
        border: none;
    }

    .message-row {
        max-width: 92%;
    }

    .quick-actions {
        grid-template-columns: 1fr;
    }

    .input-info span:last-child {
        display: none;
    }
}

@media (max-width: 400px) {
    .chat-header {
        padding: 12px 14px;
    }

    .chat-messages {
        padding: 14px;
    }

    .chat-input-area {
        padding: 12px 14px;
    }
}