/* ===== CSS Variables ===== */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #818cf8;
    --secondary-color: #8b5cf6;
    --accent-color: #06b6d4;
    --success-color: #10b981;
    --background-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --glass-bg: rgba(255, 255, 255, 0.95);
    --glass-border: rgba(255, 255, 255, 0.2);
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --border-radius-sm: 8px;
    --border-radius-md: 12px;
    --border-radius-lg: 16px;
    --border-radius-xl: 24px;
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* ===== Reset & Base Styles ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--background-gradient);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    color: var(--text-primary);
    line-height: 1.6;
}

/* ===== App Container ===== */
.app-container {
    width: 100%;
    max-width: 900px;
    height: 90vh;
    max-height: 800px;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-xl);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    border: 1px solid var(--glass-border);
    animation: fadeInUp 0.6s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== Header ===== */
.chat-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    padding: 20px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow-md);
    z-index: 10;
}

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

.logo-icon {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    animation: pulse 2s infinite;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.05);
    }
}

.header-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    letter-spacing: -0.5px;
}

.header-status {
    display: flex;
    align-items: center;
    gap: 8px;
    background: rgba(255, 255, 255, 0.15);
    padding: 6px 12px;
    border-radius: 20px;
}

.status-dot {
    width: 8px;
    height: 8px;
    background: var(--success-color);
    border-radius: 50%;
    animation: blink 1.5s infinite;
}

@keyframes blink {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.5;
    }
}

.status-text {
    color: white;
    font-size: 0.875rem;
    font-weight: 500;
}

/* ===== Main Content ===== */
.chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background: linear-gradient(180deg, #f8fafc 0%, #f1f5f9 100%);
}

/* ===== Welcome Section ===== */
.welcome-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
    text-align: center;
    animation: fadeIn 0.8s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

.welcome-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    margin-bottom: 24px;
    box-shadow: var(--shadow-lg);
    animation: float 3s ease-in-out infinite;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-10px);
    }
}

.welcome-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
    max-width: 500px;
}

.sample-question {
    background: white;
    padding: 20px 24px;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-md);
    max-width: 600px;
    border-left: 4px solid var(--primary-color);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.sample-question:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.sample-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
}

.sample-text {
    font-size: 1rem;
    color: var(--text-primary);
    font-style: italic;
}

/* ===== Messages Container ===== */
.messages-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 16px;
    padding: 24px;
    overflow-y: auto;
    scroll-behavior: smooth;
}

.messages-container::-webkit-scrollbar {
    width: 6px;
}

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

.messages-container::-webkit-scrollbar-thumb {
    background: var(--text-light);
    border-radius: 3px;
}

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

/* ===== Message Styles ===== */
.message {
    max-width: 75%;
    padding: 14px 18px;
    border-radius: var(--border-radius-lg);
    font-size: 0.95rem;
    line-height: 1.6;
    animation: messageSlide 0.3s ease-out;
    word-wrap: break-word;
}

@keyframes messageSlide {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.sent {
    align-self: flex-end;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    border-bottom-right-radius: 4px;
    box-shadow: var(--shadow-md);
}

.sent a {
    color: white;
    text-decoration: underline;
}

.received {
    align-self: flex-start;
    background: white;
    color: var(--text-primary);
    border-bottom-left-radius: 4px;
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.received a {
    color: var(--primary-color);
    text-decoration: none;
}

.received a:hover {
    text-decoration: underline;
}

/* ===== Footer ===== */
.chat-footer {
    background: white;
    padding: 20px 24px;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
    box-shadow: 0 -4px 6px -1px rgba(0, 0, 0, 0.05);
}

.input-wrapper {
    display: flex;
    gap: 12px;
    align-items: flex-end;
    background: var(--background-gradient);
    padding: 6px;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-md);
    transition: box-shadow var(--transition-normal);
}

.input-wrapper:focus-within {
    box-shadow: var(--shadow-lg);
}

.message-input {
    flex: 1;
    background: white;
    border: none;
    border-radius: var(--border-radius-md);
    padding: 14px 16px;
    font-size: 1rem;
    font-family: inherit;
    color: var(--text-primary);
    resize: none;
    outline: none;
    min-height: 50px;
    max-height: 150px;
    transition: box-shadow var(--transition-fast);
}

.message-input::placeholder {
    color: var(--text-light);
}

.message-input:focus {
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.send-button {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    border: none;
    border-radius: var(--border-radius-md);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-md);
    flex-shrink: 0;
}

.send-button:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-lg);
}

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

.send-button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.footer-hint {
    text-align: center;
    font-size: 0.75rem;
    color: var(--text-light);
    margin-top: 12px;
}

/* ===== Responsive Design ===== */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    .app-container {
        height: 95vh;
        max-height: none;
        border-radius: var(--border-radius-lg);
    }

    .chat-header {
        padding: 16px 20px;
    }

    .header-title {
        font-size: 1.25rem;
    }

    .welcome-section {
        padding: 30px 16px;
    }

    .welcome-icon {
        width: 64px;
        height: 64px;
    }

    .welcome-title {
        font-size: 1.5rem;
    }

    .welcome-subtitle {
        font-size: 1rem;
    }

    .sample-question {
        padding: 16px 20px;
    }

    .messages-container {
        padding: 16px;
        gap: 12px;
    }

    .message {
        max-width: 85%;
        padding: 12px 14px;
        font-size: 0.9rem;
    }

    .chat-footer {
        padding: 16px 20px;
    }

    .message-input {
        padding: 12px 14px;
        font-size: 0.95rem;
    }

    .send-button {
        width: 46px;
        height: 46px;
    }
}

@media (max-width: 480px) {
    .header-status {
        display: none;
    }

    .message {
        max-width: 90%;
    }

    .sample-question {
        padding: 14px 16px;
    }

    .sample-text {
        font-size: 0.9rem;
    }
}

/* ===== Loading Animation ===== */
@keyframes shimmer {
    0% {
        background-position: -200% 0;
    }

    100% {
        background-position: 200% 0;
    }
}

.loading-message {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
}