/* Base styles */
:root {
    --primary-color: #4a6fa5;
    --secondary-color: #6b8cae;
    --text-color: #333;
    --bg-color: #f5f5f5;
    --sidebar-bg: #e9eef5;
    --header-bg: #ffffff;
    --footer-bg: #ffffff;
    --border-color: #ddd;
    --button-bg: #4a6fa5;
    --button-text: #fff;
    --shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    --font-size: 16px;
}

/* Dark theme */
.dark-theme {
    --primary-color: #6b8cae;
    --secondary-color: #4a6fa5;
    --text-color: #f5f5f5;
    --bg-color: #222;
    --sidebar-bg: #333;
    --header-bg: #2c2c2c;
    --footer-bg: #2c2c2c;
    --border-color: #444;
    --button-bg: #6b8cae;
    --button-text: #fff;
    --shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
}

/* Sepia theme */
.sepia-theme {
    --primary-color: #a67c52;
    --secondary-color: #bfa980;
    --text-color: #5b4636;
    --bg-color: #f4ecd8;
    --sidebar-bg: #f1e3c6;
    --header-bg: #f4ecd8;
    --footer-bg: #f4ecd8;
    --border-color: #e0d3b8;
    --button-bg: #a67c52;
    --button-text: #fff;
    --shadow: 0 2px 5px rgba(166, 124, 82, 0.1);
}

/* Green (eye-protect) theme */
.green-theme {
    --primary-color: #4a7c59;
    --secondary-color: #a3bb98;
    --text-color: #2e4632;
    --bg-color: #e6f4ea;
    --sidebar-bg: #d2e6d8;
    --header-bg: #e6f4ea;
    --footer-bg: #e6f4ea;
    --border-color: #b7d6c2;
    --button-bg: #4a7c59;
    --button-text: #fff;
    --shadow: 0 2px 5px rgba(74, 124, 89, 0.1);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    font-size: var(--font-size);
    transition: background-color 0.3s, color 0.3s;
}

.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header styles */
header {
    background-color: var(--header-bg);
    padding: 1rem;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 10;
}

header h1 {
    color: var(--primary-color);
    font-size: 1.8rem;
}

.controls {
    display: flex;
    gap: 1rem;
}

.upload-btn {
    background-color: var(--button-bg);
    color: var(--button-text);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

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

/* Main content styles */
main {
    display: flex;
    flex: 1;
    overflow: hidden;
}

.sidebar {
    width: 250px;
    background-color: var(--sidebar-bg);
    padding: 1rem;
    overflow-y: auto;
    border-right: 1px solid var(--border-color);
    transition: transform 0.3s;
}

.sidebar h2 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.toc-container,
.bookmarks-container {
    margin-bottom: 2rem;
}

#toc,
#bookmarks {
    font-size: 0.9rem;
}

#toc a,
#bookmarks a {
    display: block;
    padding: 0.3rem 0;
    color: var(--text-color);
    text-decoration: none;
    border-bottom: 1px solid var(--border-color);
}

#toc a:hover,
#bookmarks a:hover {
    color: var(--primary-color);
}

.reader-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

#viewer {
    flex: 1;
    overflow: hidden;
    padding: 0;
    background-color: var(--bg-color);
    height: 100%;
    min-height: 0;
}

.navigation-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background-color: var(--header-bg);
    border-top: 1px solid var(--border-color);
}

.nav-btn {
    background-color: var(--button-bg);
    color: var(--button-text);
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

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

#current-page {
    font-size: 0.9rem;
}

/* Footer styles */
footer {
    background-color: var(--footer-bg);
    padding: 1rem;
    border-top: 1px solid var(--border-color);
}

.settings {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.font-size button,
.theme-toggle button {
    background-color: var(--button-bg);
    color: var(--button-text);
    border: none;
    padding: 0.5rem;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.font-size button:hover,
.theme-toggle button:hover {
    background-color: var(--secondary-color);
}

.font-size {
    display: flex;
    gap: 0.5rem;
}

/* Sidebar toggle for mobile */
.sidebar-toggle {
    display: none;
}

/* Responsive styles */
@media (max-width: 768px) {
    .sidebar-toggle {
        display: block;
        position: absolute;
        left: 0.5rem;
        top: 0.5rem;
        z-index: 1000;
    }

    header {
        position: relative;
    }

    .sidebar {
        position: fixed;
        top: 0;
        left: 0;
        height: 100%;
        transform: translateX(-100%);
        z-index: 1000;
    }

    .sidebar.active {
        transform: translateX(0);
    }

    #viewer {
        height: 100vh !important;
        position: relative;
        -webkit-overflow-scrolling: touch;
    }

    .reader-container {
        display: flex;
        flex-direction: column;
        height: calc(100vh - 10px);
    }
}

/* EPUB content styles */
#viewer iframe {
    width: 100%;
    height: 100%;
    border: none;
    display: block;
}

.translated-paragraph {
    font-size: 0.98em;
    margin-bottom: 0.5em;
    transition: color 0.2s;
}