/* --- CSS Variables and General Styling --- */
:root {
    --primary-start: #6a11cb;
    --primary-end: #2575fc;
    --accent-color: #34e89e;
    --background-gradient: linear-gradient(120deg, #a1c4fd 0%, #c2e9fb 100%);
    --text-dark: #333;
    --text-light: #fff;
    --card-bg: rgba(255, 255, 255, 0.9);
    --shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.37);
    --font-family: 'Poppins', sans-serif;
}

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

body {
    font-family: var(--font-family);
    background-image: var(--background-gradient);
    display: flex;
    flex-direction: column;
    height: 100vh;
    color: var(--text-dark);
}

/* --- Navbar --- */
.navbar {
    background: linear-gradient(90deg, var(--primary-start) 0%, var(--primary-end) 100%);
    color: var(--text-light);
    padding: 1rem 1.5rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 3px solid var(--accent-color);
}
.navbar h1 { font-weight: 600; }

/* 🔹 Make StudyBot AI ✨ link white */
.navbar h1 a {
    color: var(--text-light);
    text-decoration: none;
}
.navbar h1 a:hover {
    color: var(--accent-color); /* changes to green on hover */
}

.nav-button {
    background: var(--text-light);
    color: var(--primary-end);
    padding: 0.6rem 1.2rem;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}
.nav-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
}

/* --- Chat Container --- */
.chat-container {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    max-width: 800px;
    width: 95%;
    margin: 1rem auto;
    overflow: hidden;
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: var(--shadow);
    backdrop-filter: blur(4px);
}
#chat-messages {
    flex-grow: 1;
    overflow-y: auto;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* Chat Bubbles */
.message {
    max-width: 85%;
    padding: 0.75rem 1.25rem;
    border-radius: 24px;
    line-height: 1.6;
    word-wrap: break-word;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    animation: popIn 0.3s ease-out;
}
@keyframes popIn {
    from { opacity: 0; transform: scale(0.8); }
    to { opacity: 1; transform: scale(1); }
}

.user-message {
    background: linear-gradient(90deg, var(--primary-start) 0%, var(--primary-end) 100%);
    color: var(--text-light);
    align-self: flex-end;
    border-bottom-right-radius: 6px;
}
.bot-message {
    background: #e9e9eb;
    color: var(--text-dark);
    align-self: flex-start;
    border-bottom-left-radius: 6px;
}

/* Chat Input Form */
#chat-form {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem;
    background-color: rgba(255, 255, 255, 0.7);
    border-top: 1px solid #ddd;
}
#user-input {
    flex-grow: 1;
    border: none;
    border-radius: 50px;
    padding: 0.85rem 1.25rem;
    font-size: 1rem;
    font-family: var(--font-family);
    background-color: #f0f2f5;
    transition: box-shadow 0.3s ease;
}
#user-input:focus {
    outline: none;
    box-shadow: 0 0 0 3px var(--primary-end);
}

/* New Send Button Style */
#chat-form button {
    background: linear-gradient(90deg, var(--primary-start) 0%, var(--primary-end) 100%);
    color: var(--text-light);
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s ease;
    flex-shrink: 0;
}
#chat-form button:hover {
    transform: scale(1.1);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}
#chat-form button svg {
    width: 24px;
    height: 24px;
}

/* --- Styles for Quiz Page --- */
.quiz-container {
    max-width: 800px;
    width: 95%;
    margin: 2rem auto;
    padding: 2rem;
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: var(--shadow);
}
.hidden { display: none !important; }

#quiz-setup h2, #quiz-results h2 {
    text-align: center;
    margin-bottom: 2rem;
    font-weight: 600;
}
.form-group { margin-bottom: 1.5rem; }
.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}
.form-group input {
    width: 100%;
    padding: 0.85rem;
    border: 2px solid #ccc;
    border-radius: 8px;
    font-family: var(--font-family);
    font-size: 1rem;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}
.form-group input:focus {
    outline: none;
    border-color: var(--primary-end);
    box-shadow: 0 0 0 3px var(--primary-end);
}

/* General Quiz Buttons */
.quiz-btn {
    width: 100%;
    padding: 0.85rem;
    font-size: 1.1rem;
    font-family: var(--font-family);
    color: var(--text-light);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    text-align: center;
    transition: all 0.3s ease;
}
.quiz-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}
.quiz-btn.primary {
    background: linear-gradient(90deg, var(--primary-start) 0%, var(--primary-end) 100%);
}
.quiz-btn.success { background-color: #28a745; }
.quiz-btn.danger {
    background-color: #e74c3c;
    width: auto;
    padding: 0.5rem 1rem;
    font-size: 1rem;
}
.quiz-btn:disabled {
    background: #aaa;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* Quiz Taker */
.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}
#question-text {
    margin-bottom: 2rem;
    font-size: 1.4rem;
    font-weight: 600;
    line-height: 1.5;
}
#options-container {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.option-btn {
    padding: 0.85rem;
    text-align: left;
    background-color: #fff;
    border: 2px solid #ddd;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.2s ease;
}
.option-btn:not([disabled]):hover {
    border-color: var(--primary-end);
    background-color: #f0f8ff;
}
.option-btn.correct {
    border-color: #28a745;
    background-color: #d4edda;
    font-weight: bold;
}
.option-btn.incorrect {
    border-color: #dc3545;
    background-color: #f8d7da;
}

#quiz-results { text-align: center; }
#final-score {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 1rem;
}