:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --background-color: #f5f6fa;
    --chat-bg: #ffffff;
    --user-message-bg: #3498db;
    --bot-message-bg: #f1f2f6;
    --text-color: #2c3e50;
    --light-text: #ffffff;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

#app {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Auth Section */
.auth-section {
    text-align: center;
    padding: 50px 20px;
}

.auth-section h1 {
    font-size: 2.5em;
    margin-bottom: 20px;
}

.auth-button {
    padding: 12px 24px;
    margin: 10px;
    font-size: 1.1em;
    border: none;
    border-radius: 5px;
    background-color: var(--secondary-color);
    color: var(--light-text);
    cursor: pointer;
    transition: background-color 0.3s;
}

.auth-button:hover {
    background-color: #2980b9;
}

/* Main App */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    background-color: var(--primary-color);
    color: var(--light-text);
    border-radius: 10px 10px 0 0;
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 20px;
}

#logout-button {
    padding: 8px 16px;
    border: none;
    border-radius: 5px;
    background-color: var(--secondary-color);
    color: var(--light-text);
    cursor: pointer;
}

/* Chat Container */
.chat-container {
    background-color: var(--chat-bg);
    border-radius: 0 0 10px 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    height: 70vh;
    display: flex;
    flex-direction: column;
}

.chat-messages {
    flex-grow: 1;
    overflow-y: auto;
    padding: 20px;
}

.message {
    margin-bottom: 20px;
    max-width: 80%;
}

.message.user {
    margin-left: auto;
}

.message-content {
    padding: 12px 16px;
    border-radius: 10px;
    display: inline-block;
}

.message.bot .message-content {
    background-color: var(--bot-message-bg);
}

.message.user .message-content {
    background-color: var(--user-message-bg);
    color: var(--light-text);
}

.chat-input-container {
    padding: 20px;
    border-top: 1px solid #eee;
    display: flex;
    gap: 10px;
}

#user-input {
    flex-grow: 1;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 5px;
    resize: none;
    font-family: inherit;
}

#send-button {
    padding: 12px 24px;
    border: none;
    border-radius: 5px;
    background-color: var(--secondary-color);
    color: var(--light-text);
    cursor: pointer;
}

/* Usage Stats */
.usage-stats {
    margin-top: 20px;
    padding: 20px;
    background-color: var(--chat-bg);
    border-radius: 10px;
    display: flex;
    justify-content: space-between;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.loader {
    width: 50px;
    height: 50px;
    border: 5px solid var(--background-color);
    border-top: 5px solid var(--secondary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.hidden {
    display: none;
}