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

:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --background: #f8fafc;
    --surface: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --radius: 0.5rem;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--background);
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: 1rem;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    text-align: center;
    text-decoration: none;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
    line-height: 1;
}

.btn:hover {
    text-decoration: none;
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn:active {
    transform: translateY(0);
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    color: white;
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background-color: #475569;
    color: white;
}

.btn-success {
    background-color: var(--success-color);
    color: white;
}

.btn-error {
    background-color: var(--error-color);
    color: white;
}

.btn-block {
    display: block;
    width: 100%;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    font-size: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background-color: var(--surface);
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group.checkbox label {
    display: flex;
    align-items: center;
    font-weight: normal;
    cursor: pointer;
}

.form-group.checkbox input[type="checkbox"] {
    width: auto;
    margin-right: 0.5rem;
}

.form-help {
    display: block;
    margin-top: 0.25rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Alerts */
.alert {
    padding: 1rem;
    margin-bottom: 1rem;
    border-radius: var(--radius);
    font-size: 0.875rem;
}

.alert-success {
    background-color: #d1fae5;
    color: #065f46;
    border: 1px solid #a7f3d0;
}

.alert-error {
    background-color: #fee2e2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.alert-warning {
    background-color: #fef3c7;
    color: #92400e;
    border: 1px solid #fde68a;
}

.alert-info {
    background-color: #dbeafe;
    color: #1e40af;
    border: 1px solid #bfdbfe;
}

.alert ul {
    margin: 0;
    padding-left: 1.5rem;
}

/* Landing Page */
.landing-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem 0;
}

.hero {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--primary-color), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.tagline {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.feature {
    background: var(--surface);
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
}

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

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature h3 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.feature p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin: 0;
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Auth Pages */
.auth-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem 0;
}

.auth-box {
    background: var(--surface);
    padding: 2.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 400px;
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.auth-header h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.auth-header p {
    color: var(--text-secondary);
    margin: 0;
}

.auth-form {
    margin-bottom: 1.5rem;
}

.auth-footer {
    text-align: center;
    font-size: 0.875rem;
}

.auth-footer p {
    margin-bottom: 0.5rem;
}

.info-box {
    background-color: #eff6ff;
    border: 1px solid #bfdbfe;
    border-radius: var(--radius);
    padding: 1rem;
    font-size: 0.875rem;
    color: #1e40af;
}

/* Chat Interface */
.chat-layout {
    display: flex;
    height: 100vh;
}

.sidebar {
    width: 260px;
    background: var(--surface);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.sidebar-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-content {
    flex: 1;
    overflow-y: auto;
}

.chat-list {
    padding: 1rem;
}

.chat-item {
    display: block;
    padding: 0.75rem;
    margin-bottom: 0.5rem;
    border-radius: var(--radius);
    color: var(--text-primary);
    text-decoration: none;
    transition: background-color 0.2s;
}

.chat-item:hover {
    background-color: var(--background);
    text-decoration: none;
}

.chat-item.active {
    background-color: var(--primary-color);
    color: white;
}

.chat-item-title {
    font-weight: 500;
    margin-bottom: 0.25rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.chat-item-preview {
    font-size: 0.75rem;
    opacity: 0.7;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.chat-header {
    padding: 1rem 1.5rem;
    background: var(--surface);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 2rem;
    background-color: var(--background);
}

.message {
    margin-bottom: 1.5rem;
    display: flex;
    gap: 1rem;
}

.message-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    flex-shrink: 0;
}

.message.user .message-avatar {
    background-color: var(--secondary-color);
}

.message-content {
    flex: 1;
}

.message-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.25rem;
}

.message-author {
    font-weight: 500;
}

.message-time {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.message-text {
    background: var(--surface);
    padding: 0.75rem 1rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.message-text pre {
    background-color: var(--background);
    padding: 1rem;
    border-radius: var(--radius);
    overflow-x: auto;
    margin: 0.5rem 0;
}

.message-text code {
    background-color: var(--background);
    padding: 0.125rem 0.25rem;
    border-radius: 0.25rem;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 0.875rem;
}

.chat-input {
    padding: 1.5rem;
    background: var(--surface);
    border-top: 1px solid var(--border-color);
}

.input-wrapper {
    display: flex;
    gap: 1rem;
}

.input-wrapper textarea {
    flex: 1;
    resize: none;
    min-height: 50px;
    max-height: 150px;
}

/* Token Display */
.token-display {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background-color: var(--background);
    padding: 0.5rem 1rem;
    border-radius: var(--radius);
    font-size: 0.875rem;
}

.token-icon {
    color: var(--warning-color);
}

.token-count {
    font-weight: 600;
}

/* Loading States */
.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.typing-indicator {
    display: flex;
    gap: 0.25rem;
}

.typing-dot {
    width: 8px;
    height: 8px;
    background-color: var(--text-secondary);
    border-radius: 50%;
    animation: typing 1.4s infinite;
}

.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes typing {
    0%, 60%, 100% {
        transform: translateY(0);
        opacity: 0.7;
    }
    30% {
        transform: translateY(-10px);
        opacity: 1;
    }
}

/* Responsive */
@media (max-width: 768px) {
    .landing-page .hero h1 {
        font-size: 2rem;
    }
    
    .features {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .chat-layout {
        flex-direction: column;
    }
    
    .sidebar {
        width: 100%;
        height: auto;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }
    
    .auth-box {
        padding: 1.5rem;
        margin: 1rem;
    }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --background: #0f172a;
        --surface: #1e293b;
        --text-primary: #f1f5f9;
        --text-secondary: #94a3b8;
        --border-color: #334155;
    }
    
    .message-text code,
    .message-text pre {
        background-color: #0f172a;
    }
    
    .info-box {
        background-color: #1e3a8a;
        border-color: #2563eb;
        color: #bfdbfe;
    }
}