/* Layout System - Mobile First */

/* Body layout */
body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    padding-top: 70px; /* Account for fixed header */
    padding-bottom: 70px; /* Account for floating footer */
}

/* Paginated mode - prevent scrolling */
body.paginated {
    overflow: hidden;
    height: 100vh;
}

body.paginated .reader {
    overflow: hidden;
}

body.paginated .chapter-body {
    margin-top: var(--space-lg);
    margin-bottom: 0;
}

/* Page container for paginated content */
.page-container {
    width: 100%;
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: var(--z-header);
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    transition: transform var(--transition-fast);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 69px;
    padding: 0 var(--padding-mobile);
    max-width: var(--max-width-reader);
    margin: 0 auto;
}

.menu-btn {
    width: var(--min-touch-target);
    height: var(--min-touch-target);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-primary);
    transition: opacity var(--transition-fast);
}

.menu-btn:hover {
    opacity: 0.7;
}

.header-title {
    flex: 1;
    text-align: center;
    margin: 0 var(--space-sm);
}

.header-logo {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 var(--space-sm);
}

.header-logo-img {
    height: 28px;
    width: auto;
}

.header-progress {
    width: var(--min-touch-target);
    display: flex;
    align-items: center;
    justify-content: flex-end;
}

/* Main reading area */
.reader {
    flex: 1;
    width: 100%;
    max-width: var(--max-width-reader);
    margin: 0 auto;
    padding: var(--padding-mobile);
}

/* Chapter content */
.chapter {
    width: 100%;
}

.chapter-header {
    margin-top: 2em;
    margin-bottom: 2em;
    padding-bottom: 1.5em;
    border-bottom: 1px solid var(--color-border);
}

.chapter-body {
    margin-bottom: var(--space-2xl);
    margin-top: var(--space-lg);
}

/* Navigation footer */
.nav-footer {
    position: fixed;
    bottom: 12px;
    left: 50%;
    transform: translateX(-50%);
    z-index: var(--z-nav-footer);
    background-color: var(--color-background);
    padding: var(--space-sm) var(--space-lg);
    display: flex;
    justify-content: center;
    gap: var(--space-2xl);
    border: 2px solid var(--color-accent);
    border-radius: 0;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    padding: 2px 0;
    min-height: 24px;
    border-radius: 0;
    position: relative;
    transition: all var(--transition-fast);
}

.nav-btn::after {
    content: '';
    position: absolute;
    bottom: var(--space-sm);
    left: 0;
    right: 0;
    height: 1px;
    background-color: var(--color-accent);
    transform: scaleX(0);
    transition: transform var(--transition-fast);
}

.nav-btn:hover::after {
    transform: scaleX(1);
}

.nav-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.nav-btn:disabled::after {
    display: none;
}

.nav-btn:disabled:hover {
    background-color: transparent;
}

/* Table of Contents Sidebar */
.toc-sidebar {
    position: fixed;
    top: 0;
    right: -100%;
    width: 70%;
    max-width: 280px;
    height: 100vh;
    background-color: var(--color-background);
    box-shadow: var(--shadow-md);
    border-left: 1px solid var(--color-border);
    z-index: var(--z-sidebar);
    display: flex;
    flex-direction: column;
    transition: right var(--transition-normal);
}

.toc-sidebar.open {
    right: 0;
}

.toc-header {
    display: flex;
    align-items: center;
    padding: 0 var(--padding-mobile);
    border-bottom: 1px solid var(--color-border);
    min-height: var(--min-touch-target);
    position: relative;
}

.toc-header-icon {
    font-family: var(--font-mono);
    font-size: var(--font-size-xl);
    font-weight: bold;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
}

.close-btn {
    width: var(--min-touch-target);
    height: var(--min-touch-target);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-primary);
    transition: opacity var(--transition-fast);
    margin-left: auto;
}

.close-btn:hover {
    opacity: 0.7;
}

.toc-content {
    flex: 1;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    padding: 0;
}

.toc-footer {
    padding: var(--space-xl) var(--padding-mobile);
    border-top: 1px solid var(--color-border);
}

/* Overlay */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--color-overlay);
    z-index: var(--z-overlay);
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.overlay.active {
    opacity: 1;
    visibility: visible;
}

/* Tablet and up */
@media (min-width: 600px) {
    .header-content {
        padding: var(--space-lg) var(--padding-tablet);
    }

    .reader {
        padding: var(--padding-tablet);
    }

    .nav-footer {
        padding: var(--space-sm) var(--space-lg);
    }

    .toc-sidebar {
        width: 280px;
    }
}

/* Desktop */
@media (min-width: 1024px) {
    .reader {
        padding: var(--padding-tablet) var(--space-xl);
    }
}

/* ============================================
   HEADER TOGGLES (Reading Mode + Theme)
   ============================================ */

.header-toggles {
    display: flex;
    gap: var(--space-sm);
    align-items: center;
}

.reading-mode-toggle {
    display: flex;
    gap: 0;
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: 3px;
    overflow: hidden;
}

.mode-btn {
    padding: 4px 8px;
    font-family: var(--font-mono);
    font-size: var(--font-size-xs);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    background: transparent;
    color: var(--color-text-secondary);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

.mode-btn:hover {
    background: var(--color-accent-light);
    color: var(--color-text-primary);
}

.mode-btn.active {
    background: var(--color-text-primary);
    color: var(--color-background);
    font-weight: bold;
}

/* Scrolling mode specific styles */
body.scrolling {
    overflow: auto;
    height: auto;
}

body.scrolling .reader {
    overflow: visible;
}

body.scrolling .chapter-body {
    margin-top: var(--space-2xl);
    margin-bottom: var(--space-2xl);
}

body.scrolling .page-container p,
body.scrolling .page-container .scene-break {
    display: block !important;
}

/* Print styles */
@media print {
    .header,
    .nav-footer,
    .toc-sidebar,
    .overlay,
    .reading-mode-toggle {
        display: none;
    }

    body {
        padding: 0;
    }

    .reader {
        max-width: 100%;
    }
}