/* CSS Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    -webkit-tap-highlight-color: transparent;
}

/* CSS Variables for consistent theming */
:root {
    /* Light theme colors */
    --bg-color: #f5f5f5;
    --container-bg: #ffffff;
    --app-header-bg: #f0f0f0;
    --header-bg: #fafafa;
    --border-color: #eee;
    --text-color: #333;
    --text-muted: #888;
    --text-secondary: #6c757d;
    --highlight-color: #0066cc;
    --button-hover-bg: #f0f0f0;
    --count-highlight-bg: #e0f0ff;
    --count-highlight-color: #0066cc;
    
    /* Spacing variables */
    --spacing-xs: 0.125rem;
    --spacing-sm: 0.25rem;
    --spacing-md: 0.5rem;
    --spacing-lg: 0.75rem;
    --spacing-xl: 1rem;
    --spacing-xxl: 1.25rem;
    
    /* Border radius */
    --border-radius-sm: 0.25rem;
    --border-radius-md: 0.375rem;
    --border-radius-lg: 0.5rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.2s ease;
    --transition-slow: 0.3s ease;
    
    /* Element sizes */
    --button-size: 1.875rem;
    
    /* Animation variables for responsive tab animations */
    --tab-max-width: 10rem;
    --tab-padding-horizontal: 0.75rem;
}

/* Dark theme variables */
body.dark-mode {
    --bg-color: #1f1f1f;
    --container-bg: #121212;
    --app-header-bg: #141414;
    --header-bg: #1a1a1a;
    --border-color: #333;
    --text-color: #e0e0e0;
    --text-muted: #aaa;
    --text-secondary: #aaa;
    --button-hover-bg: #2f2f2f;
    --count-highlight-bg: #1a4771;
    --count-highlight-color: #a8d1ff;
    
    /* Tab colors for dark mode */
    --tab-bg: #2a2a2a;
    --tab-border: #404040;
    --tab-active-bg: #333333;
    --tab-active-border: #555;
    --tab-hover-color: #e0e0e0;
}

/* Base Styles */
body {
    height: 100vh;
    display: flex;
    flex-direction: column;
    background-color: var(--bg-color);
    transition: background-color var(--transition-slow);
    color: var(--text-color);
    overflow: hidden;
}

.container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    width: 100%;
    max-width: 100%;
    margin: 0 auto;
    background-color: var(--container-bg);
    transition: all var(--transition-slow);
}

.header {
    padding: var(--spacing-lg) var(--spacing-xxl);
    color: var(--text-color);
    background-color: var(--app-header-bg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
}

.title-area {
    display: flex;
    align-items: center;
    gap: 0.625rem;
}

.header h1 {
    font-size: 1.125rem;
    font-weight: 500;
}

.controls {
    display: flex;
    align-items: center;
    gap: 0.9375rem;
}

/* Tab Bar Styles */
.tab-bar {
    display: flex;
    align-items: center;
    background-color: var(--header-bg);
    padding: var(--spacing-md) var(--spacing-xxl);
    min-height: 2.5rem;
    overflow: visible;
    position: relative;
    border-bottom: 1px solid var(--border-color);
}

.tabs-container {
    display: flex;
    flex: 1;
    overflow-x: auto;
    overflow-y: visible;
    gap: 0.375rem;
    align-items: center;
    scrollbar-width: none;
    -ms-overflow-style: none;
    padding: 0;
}

.tabs-container::-webkit-scrollbar {
    display: none;
}

/* Tab Animations */
@keyframes slideInFromRight {
    from {
        opacity: 0;
        max-width: 0;
        margin-left: 0;
        margin-right: 0;
        padding-left: 0;
        padding-right: 0;
    }
    to {
        opacity: 1;
        max-width: var(--tab-max-width);
        margin-left: 0;
        margin-right: 0;
        padding-left: var(--tab-padding-horizontal);
        padding-right: var(--tab-padding-horizontal);
    }
}

@keyframes slideOutToLeft {
    from {
        transform: translateX(0);
        opacity: 1;
        max-width: var(--tab-max-width);
        margin-left: 0;
        margin-right: 0;
        padding-left: var(--tab-padding-horizontal);
        padding-right: var(--tab-padding-horizontal);
    }
    to {
        transform: translateX(-100%);
        opacity: 0;
        max-width: 0;
        margin-left: 0;
        margin-right: 0;
        padding-left: 0;
        padding-right: 0;
    }
}

@keyframes contentFadeOut {
    from {
        opacity: 1;
        transform: translateY(0);
    }
    to {
        opacity: 0;
        transform: translateY(-10px);
    }
}

@keyframes contentFadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.tab.opening {
    opacity: 0;
    max-width: 0;
    padding-left: 0;
    padding-right: 0;
    animation: slideInFromRight var(--transition-slow) ease-out forwards;
}

.tab.closing {
    animation: slideOutToLeft 0.25s ease-in forwards;
    pointer-events: none;
    overflow: hidden;
}

#page.switching-out {
    animation: contentFadeOut var(--transition-fast) ease-in forwards;
}

#page.switching-in {
    animation: contentFadeIn var(--transition-normal) ease-out forwards;
}

.tab-title {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    cursor: pointer;
}

.tab-title.editing {
    background: transparent;
    border: none;
    outline: none;
    cursor: text;
    padding: 0;
    margin: 0;
    font: inherit;
    color: inherit;
    width: 100%;
    border: 1px solid var(--highlight-color);
    border-radius: 2px;
    padding: 1px 3px;
    background-color: var(--container-bg);
}

.tab-close {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-secondary);
    padding: var(--spacing-xs);
    border-radius: var(--border-radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-normal);
    font-size: 0.75rem;
    width: 1rem;
    height: 1rem;
    flex-shrink: 0;
}

.tab-close:hover {
    background-color: #dc3545;
    color: white;
}

.tab-close:focus-visible {
    outline: 2px solid var(--highlight-color);
    outline-offset: 1px;
}

.add-tab-button, .more-button {
    background-color: #f8f9fa;
    border: 1px solid #e9ecef;
    border-radius: var(--border-radius-lg);
    cursor: pointer;
    color: var(--text-secondary);
    padding: 0.375rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-normal);
    flex-shrink: 0;
    width: var(--button-size);
    height: var(--button-size);
    opacity: 0.9;
}

.add-tab-button {
    margin-left: var(--spacing-sm);
}

.add-tab-button:hover, .more-button:hover {
    background-color: var(--container-bg);
    border-color: #dee2e6;
    color: #495057;
    opacity: 1;
}

.add-tab-button:active, .more-button:active {
    transform: scale(0.96);
    transition-duration: var(--transition-fast);
}

.add-tab-button:focus-visible, .more-button:focus-visible {
    outline: 2px solid var(--highlight-color);
    outline-offset: 2px;
}

main {
    flex: 1;
    display: flex;
    position: relative;
    z-index: 1;
}

/* Footer Styles */
.footer {
    padding: 0 var(--spacing-xxl);
    min-height: 2.5rem;
    background-color: var(--header-bg);
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
}

.footer-left {
    display: flex;
    align-items: center;
    gap: 0.625rem;
}

#page {
    flex: 1;
    width: 100%;
    padding: var(--spacing-xxl);
    border: none;
    outline: none;
    resize: none;
    font-size: 1rem;
    line-height: 1.5;
    background-color: transparent;
    color: inherit;
    touch-action: manipulation;
    content-visibility: auto;
    transition: opacity var(--transition-fast) ease-out;
}

#page.switching {
    opacity: 0.7;
}

/* Screen Mode Styles */
body.fullscreen {
    background-color: var(--container-bg);
}

body.centered .container {
    max-width: 50rem;
    height: calc(100vh - 2.5rem);
    margin: var(--spacing-xxl) auto;
    border-radius: 8px;
    box-shadow: 0 var(--spacing-sm) 1.5rem rgba(0, 0, 0, 0.08);
    overflow: hidden; /* Ensures children respect border-radius */
    transform: translateZ(0); /* Forces hardware acceleration for smoother rendering */
}

body.centered .header {
    border-radius: 8px 8px 0 0;
}

body.centered .footer {
    border-radius: 0 0 8px 8px;
}

/* Dark mode shadow adjustment */
body.dark-mode.centered .container {
    box-shadow: 0 var(--spacing-sm) 1.5rem rgba(0, 0, 0, 0.2);
}

/* Button & Counter Styles */
.header-button, .footer-button {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-muted);
    padding: var(--spacing-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color var(--transition-normal);
    border-radius: var(--border-radius-sm);
}

.header-button:hover, .footer-button:hover {
    color: var(--text-color);
}

.header-button:focus-visible, .footer-button:focus-visible {
    outline: 2px solid var(--highlight-color);
    outline-offset: 2px;
}

.header-button:focus:not(:focus-visible), .footer-button:focus:not(:focus-visible) {
    outline: none;
}

.icon {
    display: none;
    font-size: 1rem;
}

.icon.active {
    display: block;
}

.count-display {
    color: var(--text-secondary);
    font-size: 0.8125rem;
    cursor: pointer;
    user-select: none;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    transition: background-color var(--transition-normal);
}

.count-display:hover {
    background-color: var(--button-hover-bg);
}

.count-display:focus-visible {
    outline: 2px solid var(--highlight-color);
    outline-offset: 2px;
}

.count-display:focus:not(:focus-visible) {
    outline: none;
}

.count-display.highlighted {
    background-color: var(--count-highlight-bg);
    color: var(--count-highlight-color);
    font-weight: 500;
}

.count-display.highlighted:hover {
    background-color: var(--count-highlight-bg);
    filter: brightness(1.1);
}

.status {
    color: var(--text-muted);
    font-size: 0.75rem;
    opacity: 0;
    transition: opacity var(--transition-slow);
}

.status.visible {
    opacity: 1;
}

/* Tab Styles */
.tab {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.375rem 0.75rem;
    background-color: #f8f9fa;
    border: 1px solid #e9ecef;
    border-radius: var(--border-radius-lg);
    cursor: pointer;
    user-select: none;
    min-width: 6rem;
    max-width: 10rem;
    font-size: 0.8125rem;
    font-weight: 500;
    position: relative;
    white-space: nowrap;
    flex-shrink: 0;
    color: var(--text-secondary);
    height: var(--button-size);
    opacity: 0.9;
    transition: all var(--transition-normal);
}

.tab:first-child {
    margin-left: 0;
}

.tab:last-child {
    margin-right: 0;
}

.tab:not(.active) {
    padding-right: 0.75rem;
    background-color: #f8f9fa;
}

.tab:hover:not(.active) {
    background-color: var(--container-bg);
    border-color: #dee2e6;
    color: #495057;
    opacity: 1;
}

.tab.active {
    background-color: var(--container-bg);
    border-color: #dee2e6;
    color: var(--text-color);
    opacity: 1;
    z-index: 10;
    height: var(--button-size);
    padding: 0.375rem 0.75rem;
    font-weight: 600;
}

/* Dark mode tab styles */
body.dark-mode .tab {
    background-color: var(--tab-bg, #2a2a2a);
    border-color: var(--tab-border, #404040);
    color: var(--text-muted);
}

body.dark-mode .tab:hover:not(.active) {
    background-color: var(--tab-active-bg, #333333);
    border-color: var(--tab-active-border, #555);
    color: var(--tab-hover-color);
    opacity: 1;
}

body.dark-mode .tab.active {
    background-color: var(--tab-active-bg, #333333);
    border-color: var(--tab-active-border, #555);
    color: #ffffff;
    opacity: 1;
}

/* Dark mode button styles to match tabs */
body.dark-mode .add-tab-button, 
body.dark-mode .more-button {
    background-color: var(--tab-bg, #2a2a2a);
    border-color: var(--tab-border, #404040);
    color: var(--text-muted);
}

body.dark-mode .add-tab-button:hover, 
body.dark-mode .more-button:hover {
    background-color: var(--tab-active-bg, #333333);
    border-color: var(--tab-active-border, #555);
    color: var(--tab-hover-color);
    opacity: 1;
}

/* More Button and Dropdown Styles */
.more-menu-container {
    position: relative;
    margin-left: var(--spacing-sm);
}

.dropdown-menu {
    position: absolute;
    top: calc(100% + var(--spacing-md));
    right: 0;
    background-color: var(--container-bg);
    border: 1px solid #dee2e6;
    border-radius: var(--border-radius-lg);
    box-shadow: 0 var(--spacing-md) 1rem rgba(0, 0, 0, 0.15);
    padding: var(--spacing-md) 0;
    min-width: 10rem;
    z-index: 10;
    display: none;
}

.dropdown-menu.show {
    display: block;
    animation: dropdownFadeIn var(--transition-normal) ease-out forwards;
}

@keyframes dropdownFadeIn {
    from {
        opacity: 0;
        transform: translateY(-0.625rem);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.dropdown-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: 0.625rem 1rem;
    color: #495057;
    background: none;
    border: none;
    width: 100%;
    text-align: left;
    cursor: pointer;
    transition: background-color var(--transition-normal);
}

.dropdown-item:hover {
    background-color: var(--button-hover-bg);
    color: var(--text-color);
}

.dropdown-item:active {
    background-color: #e9ecef;
}

.dropdown-item:focus-visible {
    outline: none;
    background-color: #e9ecef;
}

/* Dark Mode Dropdown Styles */
body.dark-mode .dropdown-menu {
    background-color: #222;
    border-color: #444;
    box-shadow: 0 var(--spacing-md) 1rem rgba(0, 0, 0, 0.3);
}

body.dark-mode .dropdown-item {
    color: var(--text-color);
}

body.dark-mode .dropdown-item:hover {
    background-color: #2a2a2a;
    color: #fff;
}

body.dark-mode .dropdown-item:active {
    background-color: #333;
}

/* PWA Installation prompt */
#installPrompt {
    position: fixed;
    bottom: var(--spacing-xxl);
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--container-bg);
    padding: var(--spacing-lg) var(--spacing-xxl);
    border-radius: var(--border-radius-lg);
    box-shadow: 0 var(--spacing-sm) var(--spacing-lg) rgba(0, 0, 0, 0.15);
    display: none;
    align-items: center;
    gap: var(--spacing-lg);
    z-index: 100;
    max-width: 90%;
    width: 20rem;
}

#installPrompt p {
    font-size: 0.875rem;
    margin: 0;
    flex: 1;
}

#installPrompt button {
    background: var(--highlight-color);
    color: white;
    border: none;
    padding: 0.375rem 0.75rem;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    font-size: 0.8125rem;
    transition: background-color var(--transition-normal);
}

#installPrompt button:hover {
    background-color: #0055aa;
}

#installPrompt button:focus-visible {
    outline: 2px solid #ffffff;
    outline-offset: 2px;
}

#installPrompt .close {
    background: none;
    color: var(--text-muted);
    font-size: 1.125rem;
    padding: 0;
    line-height: 1;
    transition: color var(--transition-normal);
}

#installPrompt .close:hover {
    color: var(--text-color);
}

/* Media Queries */
@media (max-width: 600px) {
    :root {
        --tab-max-width: 8rem;
        --tab-padding-horizontal: var(--spacing-md);
    }
    
    body.centered .container {
        height: 100vh;
        margin: 0;
        border-radius: 0;
        box-shadow: none;
    }
    
    .header {
        padding: 0.625rem 1rem;
    }
    
    .tab-bar {
        padding: 0.375rem 0.75rem;
        min-height: 2.25rem;
    }
    
    .tabs-container {
        gap: var(--spacing-sm);
    }
    
    .tab {
        min-width: 5rem;
        max-width: var(--tab-max-width);
        padding: var(--spacing-sm) var(--tab-padding-horizontal);
        font-size: 0.75rem;
        height: 1.625rem;
        border-radius: var(--border-radius-md);
        gap: var(--spacing-sm);
    }
    
    .tab:not(.active) {
        padding-right: var(--tab-padding-horizontal);
    }
    
    .tab.active {
        height: 1.625rem;
        padding: var(--spacing-sm) var(--tab-padding-horizontal);
    }
    
    /* Mobile tabs use base animations with CSS variables */
    
    .add-tab-button, .more-button {
        padding: var(--spacing-sm);
        width: 1.625rem;
        height: 1.625rem;
        border-radius: var(--border-radius-md);
    }
    
    .add-tab-button {
        margin-left: var(--spacing-xs);
    }
    
    #page {
        padding: 1rem;
    }
    
    .controls {
        gap: 0.875rem;
    }
    
    .header-button {
        padding: var(--spacing-md);
    }
    
    .icon {
        font-size: 1.125rem;
    }
    
    .count-display {
        font-size: 0.875rem;
        padding: var(--spacing-sm) 0.375rem;
    }
    
    .footer {
        padding: 0 1rem;
        min-height: 2.25rem;
    }
    
    .footer-button {
        padding: var(--spacing-md);
    }
    
    .dropdown-menu {
        min-width: 9rem;
    }
}

/* Additional media queries for smaller devices */
@media (max-width: 380px) {
    :root {
        --tab-max-width: 6rem;
        --tab-padding-horizontal: 0.375rem;
    }
    
    .header {
        padding: var(--spacing-md) 0.75rem;
    }
    
    .header h1 {
        font-size: 1rem;
    }
    
    .controls {
        gap: 0.625rem;
    }
    
    .tab-bar {
        padding: var(--spacing-sm) var(--spacing-md);
        min-height: 2rem;
    }
    
    .tabs-container {
        gap: 0.1875rem;
    }
    
    .tab {
        min-width: 4rem;
        max-width: var(--tab-max-width);
        padding: 0.1875rem var(--tab-padding-horizontal);
        height: 1.5rem;
        border-radius: var(--border-radius-sm);
        font-size: 0.6875rem;
        gap: 0.1875rem;
    }
    
    .tab:not(.active) {
        padding-right: var(--tab-padding-horizontal);
    }
    
    .tab.active {
        height: 1.5rem;
        padding: 0.1875rem var(--tab-padding-horizontal);
    }
    
    .add-tab-button, .more-button {
        width: 1.5rem;
        height: 1.5rem;
        padding: 0.1875rem;
        border-radius: var(--border-radius-sm);
    }
    
    .count-display {
        font-size: 0.8125rem;
    }
    
    #page {
        padding: 0.75rem;
    }
    
    .footer {
        padding: 0 0.75rem;
        min-height: 2.25rem;
    }
    
    .dropdown-menu {
        min-width: 8rem;
    }
    
    .dropdown-item {
        padding: var(--spacing-md) 0.75rem;
        font-size: 0.875rem;
    }
    
    /* Small mobile tabs use base animations with CSS variables */
}

/* Landscape orientation */
@media (max-height: 500px) and (orientation: landscape) {
    .header {
        padding: 0.375rem 1rem;
    }
    
    .header h1 {
        font-size: 1rem;
    }
    
    .tab-bar {
        min-height: 2rem;
        padding: var(--spacing-sm) 0.75rem;
    }
    
    .tabs-container {
        gap: 0.1875rem;
    }
    
    .tab {
        padding: 0.1875rem var(--spacing-md);
        height: 1.5rem;
        border-radius: var(--border-radius-sm);
        font-size: 0.75rem;
        gap: 0.1875rem;
    }
    
    .tab:not(.active) {
        padding-right: var(--spacing-md);
    }
    
    .tab.active {
        height: 1.5rem;
        padding: 0.1875rem var(--spacing-md);
    }
    
    .add-tab-button, .more-button {
        width: 1.5rem;
        height: 1.5rem;
        padding: 0.1875rem;
        border-radius: var(--border-radius-sm);
    }
    
    #page {
        padding: 0.625rem 1rem;
    }
    
    .footer {
        padding: 0 1rem;
        min-height: 2rem;
    }
}