:root {
    /* Dark Theme Colors */
    --bg-page: #121212;
    --bg-sidebar: #181818;
    --bg-header: #1e1e1e;
    --bg-column: #1a1a1a;
    --bg-card: #2d2d2d;
    --bg-card-hover: #3d3d3d;
    
    --text-primary: #ffffff;
    --text-secondary: #aaaaaa;
    
    --border-color: #333333;
    
    --color-primary: #8be9fd;    /* Cyan */
    --color-danger: #ff5555;     /* Red */

    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-page);
    color: var(--text-primary);
    overflow: hidden;
    height: 100dvh; /* Critical fix for mobile browsers */
    width: 100vw;
}

/* --- Layout --- */
.app-container {
    display: flex;
    height: 100%;
    width: 100%;
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 100dvh;
    min-width: 0; /* Prevents flex blowout */
}

/* --- Drawer (Sidebar) --- */
.drawer-overlay {
    position: fixed;
    inset: 0;
    background-color: rgba(0, 0, 0, 0.6);
    z-index: 1999;
    opacity: 1;
    transition: opacity 0.3s ease;
}

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

.sidebar {
    position: fixed;
    top: 0;
    left: -300px;
    width: 280px;
    height: 100dvh;
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 1.5rem 1rem;
    z-index: 2000;
    transition: left 0.3s ease;
    box-shadow: 5px 0 15px rgba(0,0,0,0.5);
}

.sidebar.open {
    left: 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--color-primary);
    letter-spacing: 1px;
    margin-bottom: 2rem;
    text-align: center;
}

.sidebar-section {
    display: flex;
    flex-direction: column;
    flex: 1;
    overflow-y: auto;
}

.sidebar-section h3 {
    font-size: 0.8rem;
    text-transform: uppercase;
    color: var(--text-secondary);
    margin-bottom: 0.8rem;
    letter-spacing: 0.5px;
}

.board-list {
    list-style: none;
    margin-bottom: 1rem;
}

.board-list li {
    padding: 0.8rem 1rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    color: var(--text-secondary);
    transition: background-color 0.2s, color 0.2s;
    margin-bottom: 0.2rem;
}

.board-list li:hover {
    background-color: var(--bg-card);
    color: var(--text-primary);
}

.board-list li.active {
    background-color: var(--color-primary);
    color: #000;
    font-weight: bold;
}

#add-board-btn {
    margin-top: auto;
}

.text-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    text-align: left;
    padding: 0.5rem;
    font-size: 0.9rem;
    transition: color 0.2s;
}

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

/* --- Header --- */
.app-header {
    background-color: var(--bg-header);
    padding: 1rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0; /* Ensures header never shrinks */
}

.header-left {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.menu-btn {
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 1.8rem;
    cursor: pointer;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.2s;
}

.menu-btn:hover {
    color: var(--color-primary);
}

.header-left h1 {
    font-size: 1.3rem;
}

.tag-filters {
    display: flex;
    gap: 0.5rem;
}

.tag-filter-btn {
    background: var(--bg-page);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 0.4rem 0.8rem;
    cursor: pointer;
    border-radius: 20px;
    font-size: 0.8rem;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.tag-filter-btn.active {
    border-color: currentColor;
    background-color: rgba(255,255,255,0.1);
    color: var(--text-primary);
}

/* --- Buttons --- */
button {
    font-family: inherit;
}

.primary-btn, .secondary-btn, .danger-btn {
    padding: 0.6rem 1.2rem;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: bold;
    transition: opacity 0.2s, transform 0.1s;
}

.primary-btn {
    background-color: var(--color-primary);
    color: #000;
}

.secondary-btn {
    background-color: var(--bg-card);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.danger-btn {
    background-color: var(--color-danger);
    color: #fff;
}

.primary-btn:hover, .secondary-btn:hover, .danger-btn:hover {
    opacity: 0.9;
}
.primary-btn:active, .secondary-btn:active, .danger-btn:active {
    transform: scale(0.98);
}

/* --- Board Layout --- */
.board {
    display: flex;
    flex: 1;
    padding: 1rem;
    gap: 1.5rem;
    overflow-x: auto;
    overflow-y: hidden; /* Prevent full board scroll */
    min-height: 0; /* Critical flexbox fix to allow children to shrink */
}

.column {
    background-color: var(--bg-column);
    border-radius: var(--radius-md);
    min-width: 320px;
    width: 320px;
    display: flex;
    flex-direction: column;
    height: 100%; /* Take full height of .board */
}

.column-header {
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 2px solid var(--border-color);
    flex-shrink: 0;
}

.column-header h2 {
    font-size: 1.1rem;
    font-weight: 600;
}

.task-count {
    background-color: var(--bg-card);
    color: var(--text-secondary);
    padding: 0.2rem 0.6rem;
    border-radius: 12px;
    font-size: 0.8rem;
}

.column-body {
    padding: 1rem;
    flex: 1;
    overflow-y: auto; /* ONLY the tasks should scroll */
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    min-height: 100px;
    -webkit-overflow-scrolling: touch;
}

.column-body.drag-over {
    background-color: rgba(255, 255, 255, 0.05);
}

/* --- Cards --- */
.task-card {
    background-color: var(--bg-card);
    border-radius: var(--radius-sm);
    padding: 1rem;
    cursor: grab;
    border-left: 4px solid var(--border-color);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: transform 0.2s, box-shadow 0.2s, background-color 0.2s;
    user-select: none;
    flex-shrink: 0; /* Prevents cards from squishing */
}

.task-card:hover {
    background-color: var(--bg-card-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

.task-card:active {
    cursor: grabbing;
}

.task-card.dragging {
    opacity: 0.5;
    transform: scale(0.95);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.5rem;
}

.card-title {
    font-weight: 600;
    font-size: 1rem;
    line-height: 1.3;
    word-break: break-word;
}

.card-actions {
    display: flex;
    gap: 0.5rem;
}

.edit-icon, .link-icon {
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 1.1rem;
    transition: color 0.2s;
    text-decoration: none;
}

.edit-icon:hover, .link-icon:hover {
    color: var(--color-primary);
}

.card-tags {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.tag {
    font-size: 0.7rem;
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-weight: bold;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* --- Modals --- */
.modal {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100dvh;
    background-color: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 3000;
    opacity: 1;
    transition: opacity 0.2s;
}

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

.modal-content {
    background-color: var(--bg-column);
    width: 90%;
    max-width: 500px;
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    border: 1px solid var(--border-color);
    max-height: 90dvh;
    overflow-y: auto;
}

.modal-content.modal-large {
    max-width: 700px;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.close-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 1.5rem;
    cursor: pointer;
}

.close-btn:hover {
    color: var(--text-primary);
}

.form-group {
    margin-bottom: 1.2rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.4rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.form-group input, 
.form-group select, 
.form-group textarea {
    width: 100%;
    padding: 0.8rem;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
}

.form-group input:focus, 
.form-group select:focus, 
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
}

.settings-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.settings-col h3 {
    font-size: 1rem;
    margin-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.dynamic-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.dynamic-item {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.dynamic-item input {
    padding: 0.5rem;
    font-size: 0.9rem;
}

.dynamic-item input[type="color"] {
    padding: 0;
    width: 40px;
    height: 38px;
    cursor: pointer;
}

.remove-item-btn {
    background: none;
    border: none;
    color: var(--color-danger);
    cursor: pointer;
    font-size: 1.2rem;
    padding: 0 0.5rem;
}

.modal-actions {
    display: flex;
    justify-content: space-between;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

.right-actions {
    display: flex;
    gap: 1rem;
}

.hidden {
    display: none !important;
}

/* --- Toast --- */
.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--bg-card);
    color: var(--text-primary);
    padding: 1rem 1.5rem;
    border-radius: var(--radius-sm);
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
    border-left: 4px solid var(--color-primary);
    transition: opacity 0.3s, transform 0.3s;
    z-index: 4000;
}

.toast.error {
    border-left-color: var(--color-danger);
}

/* --- Scrollbar --- */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-color); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-secondary); }

/* --- Mobile Responsiveness --- */
@media (max-width: 768px) {
    .app-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
        padding: 1rem;
    }

    .header-left {
        width: 100%;
        gap: 1rem;
    }

    .tag-filters {
        overflow-x: auto;
        width: 100%;
        padding-bottom: 0.5rem;
        -webkit-overflow-scrolling: touch;
    }

    .header-right {
        display: flex;
        width: 100%;
        justify-content: space-between;
        gap: 0.5rem;
    }

    .header-right button {
        flex: 1;
        padding: 0.6rem;
    }

    .board {
        scroll-snap-type: x mandatory;
        -webkit-overflow-scrolling: touch;
        padding-bottom: 1.5rem; /* Extra padding for bottom swiping clearance */
    }

    .column {
        min-width: 85vw;
        width: 85vw;
        scroll-snap-align: center;
    }

    .settings-grid {
        grid-template-columns: 1fr;
    }

    .modal-content {
        padding: 1.5rem;
        width: 95%;
    }
    
    .modal-actions {
        flex-direction: column;
        gap: 1rem;
    }
    
    .right-actions {
        width: 100%;
        display: flex;
        justify-content: space-between;
        gap: 1rem;
    }
    
    .right-actions button, .danger-btn {
        flex: 1;
        text-align: center;
    }
}