/* CSS reset and base styles */
:root {
    --bg-color: #f7f9f9;
    --text-color: #2c3e50;
    --text-muted: #7f8c8d;
    --primary-color: #3498db;
    --surface-color: #ffffff;
    --border-color: #ecf0f1;
    --shadow: 0 4px 12px rgba(0,0,0,0.05);
    
    --font-serif: 'Noto Serif SC', serif;
    --font-sans: 'Noto Sans SC', sans-serif;
    --font-yahei: 'Microsoft YaHei', 'PingFang SC', sans-serif;
    --font-kaiti: 'KaiTi', 'Kaiti SC', STKaiti, var(--font-serif);
    --font-fangsong: 'FangSong', 'FangSong_GB2312', STFangsong, var(--font-serif);
    --font-wenkai: 'LXGW WenKai Lite', var(--font-sans);
    --font-custom: 'CustomReaderFont', var(--font-serif);
    
    --content-width: 800px;
    --transition-speed: 0.3s;
    
    --outer-bg: var(--border-color);
    --outer-bg-img: none;
    --paper-bg-img: none;
    --font-weight-reader: 400;
    
    --outer-bg-size: cover;
    --outer-bg-repeat: no-repeat;
    --paper-bg-size: cover;
    --paper-bg-repeat: no-repeat;
}

@font-face {
    font-family: 'CustomReaderFont';
    src: var(--custom-font-url, local('Arial')); /* Injected by JS */
}

/* Themes */
body.theme-light {
    --bg-color: #fdfdfd;
    --text-color: #2b2b2b;
    --surface-color: #ffffff;
    --border-color: #eef2f5;
    --outer-bg: #eef2f5;
}

body.theme-sepia {
    --bg-color: #fbf0e6;
    --text-color: #5b4636;
    --surface-color: #fbf0e6;
    --border-color: #e4d5b7;
    --outer-bg: #e4d5b7;
}

body.theme-dark {
    --bg-color: #1a1a1a;
    --text-color: #d4d4d4;
    --surface-color: #252525;
    --border-color: #3a3a3a;
    --outer-bg: #0d0d0d;
    --shadow: 0 4px 12px rgba(0,0,0,0.4);
}

/* Base Body Styles */
body {
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-serif);
    transition: background-color var(--transition-speed), color var(--transition-speed), background-image var(--transition-speed);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body.font-sans {
    font-family: var(--font-sans);
}

body.font-serif {
    font-family: var(--font-serif);
}

body.font-yahei {
    font-family: var(--font-yahei);
}

body.font-kaiti {
    font-family: var(--font-kaiti);
}

body.font-fangsong {
    font-family: var(--font-fangsong);
}

body.font-wenkai {
    font-family: var(--font-wenkai);
}

body.font-custom {
    font-family: var(--font-custom);
}

/* Custom Outer Backgrounds (Only visible in Card Mode) */
body.layout-card.outer-wood {
    --outer-bg-img: url('https://www.transparenttextures.com/patterns/wood-pattern.png');
    --outer-bg: #cda87c;
    --outer-bg-size: auto;
    --outer-bg-repeat: repeat;
}
body.layout-card.outer-paper {
    --outer-bg-img: url('https://www.transparenttextures.com/patterns/cream-paper.png');
    --outer-bg: #e5e0d8;
    --outer-bg-size: auto;
    --outer-bg-repeat: repeat;
}
body.layout-card.outer-grid {
    --outer-bg-img: url('https://www.transparenttextures.com/patterns/graphy.png');
    --outer-bg: #eaeff2;
    --outer-bg-size: auto;
    --outer-bg-repeat: repeat;
}
body.layout-card.outer-starry {
    --outer-bg-img: url('https://www.transparenttextures.com/patterns/stardust.png');
    --outer-bg: #1a2230;
    --outer-bg-size: auto;
    --outer-bg-repeat: repeat;
}
body.layout-card.outer-night {
    --outer-bg-img: none;
    --outer-bg: #111111;
}
body.layout-card.outer-default {
    --outer-bg-img: none;
}

body.layout-card {
    background-color: var(--outer-bg);
    background-image: var(--outer-bg-img);
    background-size: var(--outer-bg-size);
    background-repeat: var(--outer-bg-repeat);
    background-position: center;
}

/* Toolbar */
.toolbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background-color: rgba(255, 255, 255, 0.85); /* fallback */
    background-color: color-mix(in srgb, var(--surface-color) 85%, transparent);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    box-shadow: var(--shadow);
    z-index: 100;
    transform: translateY(0);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), background-color var(--transition-speed);
}

.toolbar.hidden {
    transform: translateY(-100%);
}

.toolbar-content {
    max-width: var(--content-width);
    margin: 0 auto;
    height: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
}

.book-title {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--text-muted);
}

button.icon-button {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s;
}

button.icon-button:hover {
    background-color: var(--border-color);
}

/* Reader Container */
.reader-container {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 120px 40px 80px; /* Generous padding for desktop reading */
    min-height: 100vh;
    box-sizing: border-box;
    transition: background-color var(--transition-speed), box-shadow var(--transition-speed), border-radius var(--transition-speed), transform var(--transition-speed), margin var(--transition-speed), background-image var(--transition-speed);
}

body.layout-card .reader-container {
    background-color: var(--surface-color);
    background-image: var(--paper-bg-img);
    background-size: var(--paper-bg-size);
    background-position: center;
    background-repeat: var(--paper-bg-repeat);
    box-shadow: 0 8px 32px rgba(0,0,0,0.08);
    margin-top: 60px;
    min-height: calc(100vh - 60px);
    border-radius: 12px 12px 0 0;
}

body.theme-dark.layout-card .reader-container {
    box-shadow: 0 8px 32px rgba(0,0,0,0.5); /* Stronger shadow in dark mode */
}

body.layout-flat .reader-container {
    background-color: transparent;
    box-shadow: none;
    margin-top: 0;
    border-radius: 0;
}

#content-display {
    font-size: 18px; /* Managed by JS */
    line-height: 1.8; /* Managed by JS */
}

/* Typography styles for content */
#content-display p {
    text-indent: 2em; /* Chinese typography standard */
    margin-bottom: 1.2em;
    text-align: justify;
    word-break: break-word;
    white-space: pre-wrap;
    font-weight: var(--font-weight-reader);
    transition: font-size 0.2s, line-height 0.2s, font-weight 0.2s;
}

/* Chapter Header Aesthetics */
.chapter-header {
    text-align: center;
    margin-top: 2em;
    margin-bottom: 4em;
}

.chapter-title {
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--text-color);
    margin: 0;
    letter-spacing: 0.1em;
    font-family: inherit; /* Matches body font */
}

.chapter-divider {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: 1.5em;
    opacity: 0.4;
}

.chapter-divider .line {
    width: 60px;
    height: 1px;
    background-color: var(--text-color);
    margin: 0 15px;
}

.chapter-divider .diamond {
    width: 6px;
    height: 6px;
    background-color: var(--text-color);
    transform: rotate(45deg);
}

/* Settings Overlay */
.settings-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0,0,0,0.5);
    backdrop-filter: blur(2px);
    z-index: 200;
    display: flex;
    justify-content: flex-end;
    opacity: 1;
    transition: opacity 0.3s;
}

.settings-overlay.overlay-hidden {
    opacity: 0;
    pointer-events: none;
}

.settings-panel {
    background-color: var(--surface-color);
    width: 340px;
    height: 100%;
    box-shadow: -4px 0 24px rgba(0,0,0,0.15);
    transform: translateX(0);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), background-color var(--transition-speed);
    padding: 24px;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    gap: 24px;
    overflow-y: auto;
}

.overlay-hidden .settings-panel {
    transform: translateX(100%);
}

.settings-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 16px;
}

.settings-header h3 {
    margin: 0;
    font-size: 1.25rem;
    color: var(--text-color);
    font-weight: 500;
}

.settings-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.sub-settings {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 8px 12px;
    background-color: var(--border-color);
    border-radius: 8px;
    margin-top: 4px;
}

.settings-group label {
    font-size: 0.95rem;
    color: var(--text-muted);
    font-weight: 500;
    display: flex;
    justify-content: space-between;
}

.settings-group label span {
    color: var(--text-color);
    font-weight: 700;
}

.button-group {
    display: flex;
    background-color: var(--border-color);
    border-radius: 8px;
    padding: 4px;
    gap: 4px;
}

.button-group .btn {
    flex: 1;
    background: transparent;
    border: none;
    padding: 10px 0;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.95rem;
    color: var(--text-muted);
    transition: background-color 0.2s, color 0.2s, box-shadow 0.2s;
}

.button-group .btn:hover {
    color: var(--text-color);
}

.button-group .btn.active {
    background-color: var(--surface-color);
    box-shadow: var(--shadow);
    color: var(--text-color);
    font-weight: 600;
}

/* Slider Customization */
.slider {
    -webkit-appearance: none;
    width: 100%;
    height: 4px;
    background: var(--border-color);
    outline: none;
    border-radius: 4px;
    margin: 10px 0;
}

.slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--surface-color);
    border: 2px solid var(--text-color);
    cursor: pointer;
    transition: transform 0.1s;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.slider::-webkit-slider-thumb:hover {
    transform: scale(1.15);
}

.slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--surface-color);
    border: 2px solid var(--text-color);
    cursor: pointer;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

/* Tooltip Styles */
.selection-tooltip {
    position: absolute;
    background-color: rgba(30, 30, 30, 0.85);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    color: #fff;
    padding: 6px 12px;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
    z-index: 1000;
    display: flex;
    align-items: center;
    gap: 8px;
    pointer-events: auto;
    transform: translate(-50%, -100%);
    margin-top: -10px;
    transition: opacity 0.2s, transform 0.2s;
    opacity: 1;
}

.selection-tooltip::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 50%;
    transform: translateX(-50%);
    border-width: 6px 6px 0;
    border-style: solid;
    border-color: rgba(30, 30, 30, 0.85) transparent transparent transparent;
}

.selection-tooltip.hidden {
    opacity: 0;
    pointer-events: none;
    transform: translate(-50%, -80%); /* slight upward slide effect */
}

.selection-tooltip button {
    background: none;
    border: none;
    color: #fff;
    font-size: 14px;
    cursor: pointer;
    padding: 4px;
    transition: color 0.2s;
}

.selection-tooltip button:hover {
    color: var(--primary-color);
}

.selection-tooltip .divider {
    width: 1px;
    height: 14px;
    background-color: rgba(255,255,255,0.3);
}

/* Crop Modal Styles */
.crop-modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0,0,0,0.85);
    backdrop-filter: blur(8px);
    z-index: 9999;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    opacity: 1;
    transition: opacity 0.3s;
}

.crop-modal.hidden {
    display: none;
}

.crop-container {
    width: 90vw;
    height: 75vh;
    max-width: 1000px;
    background-color: #1a1a1a;
    border-radius: 12px;
    overflow: hidden;
    position: relative;
    box-shadow: 0 12px 48px rgba(0,0,0,0.5);
}

.crop-container img {
    display: block;
    max-width: 100%;
    max-height: 100%;
}

.crop-toolbar {
    margin-top: 24px;
    display: flex;
    gap: 16px;
    padding: 12px 24px;
    background-color: #222;
    border-radius: 30px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.4);
    align-items: center;
}

.crop-toolbar .btn {
    border: none;
    background-color: #333;
    color: #ddd;
    padding: 10px 20px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: all 0.2s;
}

.crop-toolbar .btn:hover {
    background-color: #444;
    color: #fff;
}

.crop-toolbar .btn-tool.active {
    background-color: var(--primary-color);
    color: white;
}

.crop-toolbar .btn-primary {
    background-color: #2ecc71;
    color: white;
    font-weight: bold;
    padding: 10px 32px;
}

.crop-toolbar .btn-primary:hover {
    background-color: #27ae60;
}

.crop-ratios {
    display: flex;
    gap: 8px;
    border-left: 1px solid #444;
    border-right: 1px solid #444;
    padding: 0 16px;
}

/* Mobile Adjustments */
@media (max-width: 768px) {
    .reader-container {
        padding: 80px 20px 60px;
    }
    
    .chapter-title {
        font-size: 1.8rem;
    }
    
    body.layout-card .reader-container {
        margin-top: 40px;
        min-height: calc(100vh - 40px);
        border-radius: 16px 16px 0 0;
    }

    #content-display p {
        margin-bottom: 1em;
    }
    
    .settings-panel {
        width: 100%;
        border-radius: 20px 20px 0 0;
        height: auto;
        position: absolute;
        bottom: 0;
        top: auto;
        max-height: 85vh;
        transform: translateY(0);
    }
    
    .overlay-hidden .settings-panel {
        transform: translateY(100%);
    }
}