/* --- Global Styles & Variables --- */
:root {
    --primary-color: #6a11cb;
    --secondary-color: #2575fc;
    --background-color: #f4f7f6;
    --card-bg-color: #ffffff;
    --text-color: #333;
    --light-text-color: #777;
    --white-color: #fff;
    --danger-color: #e74c3c;
    --success-color: #2ecc71;
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-color);
}

/* --- Page & Layout --- */
.page {
    min-height: 100vh;
    width: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.page-content {
    width: 100%;
    max-width: 400px;
    text-align: center;
}

.with-header {
    padding-top: 80px; /* Space for fixed header */
}

.with-footer {
    padding-bottom: 80px; /* Space for fixed footer */
}

.hidden {
    display: none !important;
}

h1 {
    font-size: 2.2rem;
    color: var(--primary-color);
    margin-bottom: 10px;
}

h2 {
    width: 100%;
    text-align: left;
    font-size: 1.8rem;
    color: var(--text-color);
    margin-bottom: 20px;
}

/* --- Header & Footer --- */
#app-header, #app-footer {
    position: fixed;
    left: 0;
    width: 100%;
    background: var(--white-color);
    box-shadow: var(--box-shadow);
    z-index: 100;
}

#app-header {
    top: 0;
    height: 60px;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
    padding: 0 20px;
}

.app-name {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

#app-header .fa-search {
    font-size: 1.4rem;
    cursor: pointer;
}

#app-footer {
    bottom: 0;
    height: 65px;
    border-top: 1px solid #eee;
}

#app-footer nav {
    display: flex;
    justify-content: space-around;
    align-items: center;
    height: 100%;
}

.nav-link {
    display: flex;
    flex-direction: column;
    align-items: center;
    color: var(--light-text-color);
    text-decoration: none;
    font-size: 0.8rem;
    transition: color 0.3s;
}

.nav-link i {
    font-size: 1.5rem;
    margin-bottom: 4px;
}

.nav-link.active {
    color: var(--primary-color);
}

/* --- Forms & Buttons --- */
form {
    display: flex;
    flex-direction: column;
    gap: 15px;
    width: 100%;
}

input, select {
    width: 100%;
    padding: 15px;
    border: 1px solid #ccc;
    border-radius: var(--border-radius);
    font-size: 1rem;
}

button {
    padding: 15px;
    border: none;
    border-radius: var(--border-radius);
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
    color: var(--white-color);
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(0,0,0,0.15);
}

.back-button {
    align-self: flex-start;
    margin-bottom: 20px;
    background: #eee;
    color: var(--text-color);
    font-size: 1rem;
    padding: 10px 15px;
}

.message {
    margin-top: 15px;
    font-weight: bold;
}

/* --- Cards --- */
.grid-container {
    width: 100%;
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
}

.course-card {
    background: var(--card-bg-color);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.course-card img {
    width: 100%;
    height: 180px;
    object-fit: cover;
}

.course-card-content {
    padding: 15px;
}

.course-card h3 {
    margin-bottom: 8px;
    font-size: 1.2rem;
}

.course-card p {
    font-size: 0.9rem;
    color: var(--light-text-color);
    margin-bottom: 15px;
}

.course-card button {
    width: 100%;
    font-size: 1rem;
}
.course-card button.view-btn {
    background: var(--success-color);
}


/* --- Profile Page --- */
.profile-card {
    width: 100%;
    background: var(--card-bg-color);
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    text-align: left;
}
.profile-card p {
    font-size: 1.1rem;
    margin-bottom: 15px;
}
.profile-card strong {
    color: var(--primary-color);
}
.profile-actions {
    width: 100%;
    margin-top: 20px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.profile-btn {
    background: var(--card-bg-color);
    color: var(--text-color);
    border: 1px solid #eee;
    text-align: left;
    padding: 15px;
    display: flex;
    align-items: center;
    gap: 15px;
    font-weight: normal;
}
.profile-btn.danger {
    color: var(--danger-color);
}

/* --- Unit/Detail Pages --- */
#units-list, #unit-content {
    width: 100%;
}
.unit-item {
    background: var(--white-color);
    padding: 20px;
    margin-bottom: 10px;
    border-radius: var(--border-radius);
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    transition: background-color 0.3s;
}
.unit-item:hover {
    background-color: #f0f0f0;
}
.unit-item.completed {
    color: var(--light-text-color);
    background-color: #e9f7ef;
}
.unit-item.completed .fa-check-circle {
    color: var(--success-color);
}

#video-container, #audio-container, #text-container {
    margin-bottom: 20px;
}
video {
    width: 100%;
    border-radius: var(--border-radius);
}
audio {
    width: 100%;
}
#text-container {
    background: var(--white-color);
    padding: 20px;
    border-radius: var(--border-radius);
    line-height: 1.6;
    text-align: left;
}

/* --- Chat Bot Button --- */
#chat-bot-btn {
    position: fixed;
    bottom: 85px; /* Above footer */
    right: 20px;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    font-size: 1.8rem;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 101;
}

/* --- Miscellaneous --- */
.app-icon-large {
    width: 100px;
    height: 100px;
    border-radius: 20px;
    margin-bottom: 20px;
}
.text-center {
    text-align: center;
}

/* --- Responsive Desktop Styles --- */
@media (min-width: 768px) {
    .page-content {
        max-width: 600px;
    }

    #home-page, #my-book-page {
        padding-left: 40px;
        padding-right: 40px;
    }

    .grid-container {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .grid-container {
        grid-template-columns: repeat(3, 1fr);
    }
}