:root {
    /* Color Palette */
    --primary-color: #008080; /* Teal */
    --secondary-color: #E6F3F3; /* Light Teal */
    --background-color: #F8F9FA; /* Off-White */
    --user-bubble-color: #D4F4F4; /* Lighter Teal */
    --ai-bubble-color: #FFFFFF; /* White */
    --text-color: #333333; /* Dark Gray */
    --border-color: #E0E0E0;
    
    /* Fonts and Shadows */
    --font-family: 'Poppins', sans-serif;
    --shadow-soft: 0 4px 20px rgba(0, 0, 0, 0.08);
}

body {
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.app-container {
    width: 100%;
    max-width: 500px;
    height: 90vh;
    display: flex;
    flex-direction: column;
    background-color: var(--ai-bubble-color);
    border-radius: 20px;
    box-shadow: var(--shadow-soft);
    overflow: hidden;
    transition: box-shadow 0.3s ease;
}

.app-header {
    background-color: var(--primary-color);
    color: #fff;
    padding: 2rem 1.5rem;
    position: relative;
    text-align: center;
}

.logo {
    font-weight: 600;
    font-size: 1.8rem;
    margin: 0;
    letter-spacing: 0.5px;
}

.chat-main {
    flex: 1;
    overflow-y: auto;
    padding: 1.5rem;
    background-color: var(--background-color);
    display: flex;
    flex-direction: column;
}

.chat-main::-webkit-scrollbar {
    width: 6px;
}

.chat-main::-webkit-scrollbar-thumb {
    background-color: var(--secondary-color);
    border-radius: 3px;
}

.mood-tracker-card {
    background-color: var(--ai-bubble-color);
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.mood-prompt {
    font-weight: 500;
    font-size: 1.1rem;
    color: var(--text-color);
    margin: 0;
}

.mood-buttons {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.mood-btn {
    font-size: 2.5rem;
    background-color: transparent;
    border: none;
    cursor: pointer;
    transition: transform 0.3s ease, filter 0.3s ease;
    filter: grayscale(100%);
    opacity: 0.8;
}

.mood-btn:hover {
    transform: scale(1.15);
    filter: grayscale(0%);
    opacity: 1;
}

.mood-btn.selected {
    transform: scale(1.3);
    filter: grayscale(0%);
    opacity: 1;
    animation: pop 0.3s ease-in-out;
}

.chat-box {
    display: flex;
    flex-direction: column;
}

.message {
    max-width: 85%;
    padding: 1rem 1.4rem;
    border-radius: 20px;
    margin-bottom: 1rem;
    line-height: 1.5;
    word-wrap: break-word;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
    transition: transform 0.2s ease;
}

.ai-msg {
    background-color: var(--ai-bubble-color);
    color: var(--text-color);
    align-self: flex-start;
    border-bottom-left-radius: 6px;
}

.user-msg {
    background-color: var(--user-bubble-color);
    color: var(--text-color);
    align-self: flex-end;
    border-top-right-radius: 6px;
}

.input-area {
    display: flex;
    align-items: center;
    padding: 1rem;
    background-color: var(--ai-bubble-color);
    border-top: 1px solid var(--border-color);
    gap: 0.75rem;
}

#user-input {
    flex: 1;
    padding: 0.8rem 1.2rem;
    border: 1px solid var(--border-color);
    border-radius: 25px;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

#user-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(0, 128, 128, 0.2);
}

.send-btn {
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 50%;
    width: 45px;
    height: 45px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.2s;
    box-shadow: 0 2px 5px rgba(0, 128, 128, 0.1);
}

.send-btn:hover {
    background-color: #006666;
    transform: scale(1.05);
}

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

.disclaimer {
    font-size: 0.7rem;
    text-align: center;
    color: #888;
    padding: 1rem;
    border-top: 1px solid var(--border-color);
}

@keyframes pop {
    0% { transform: scale(1); }
    50% { transform: scale(1.4); }
    100% { transform: scale(1.3); }
}

@media (max-width: 600px) {
    .app-container {
        height: 100vh;
        border-radius: 0;
        box-shadow: none;
    }
}