:root {
    --bg-color: #f8fafc;
    --header-bg: rgba(255, 255, 255, 0.85);
    --col-bg: #f1f5f9;
    --card-bg: #ffffff;

    --text-main: #0f172a;
    --text-muted: #64748b;
    --text-light: #94a3b8;

    --primary: #0f172a;
    --primary-hover: #334155;
    --danger: #ef4444;
    --success: #10b981;

    --border: #e2e8f0;
    --border-hover: #cbd5e1;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
    --shadow-float: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -2px rgba(0, 0, 0, 0.04);

    --radius-lg: 16px;
    --radius-md: 12px;
    --radius-sm: 8px;

    --pri-low: #10b981;
    --pri-med: #eab308;
    --pri-high: #f97316;
    --pri-crit: #ef4444;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

@media (min-width: 768px) {
    body { height: 100vh; overflow: hidden; }
}

/* --- UTILITY --- */
.hidden { display: none !important; }

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

@media (min-width: 768px) {
    #app { height: 100vh; overflow: hidden; }
}

/* --- LOADING --- */
.loading {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-color);
    font-size: 16px;
    font-weight: 500;
    color: var(--text-muted);
    z-index: 9999;
}

/* --- SCROLLBARS --- */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: #94a3b8; }

/* --- HEADER --- */
.header {
    background-color: var(--header-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 16px 24px;
    border-bottom: 1px solid var(--border);
    z-index: 10;
    flex-shrink: 0;
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.header-title-group {
    display: flex;
    align-items: center;
    gap: 12px;
}

.app-title {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.user-profile {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-muted);
}

.user-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: linear-gradient(135deg, #6366f1, #a855f7);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 600;
    box-shadow: var(--shadow-sm);
}

/* --- FILTER SELECT --- */
.filter-select {
    padding: 5px 28px 5px 10px;
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    font-family: 'Inter', sans-serif;
    background: #f1f5f9;
    color: var(--text-main);
    cursor: pointer;
    outline: none;
    flex-shrink: 0;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 8px center;
}

.btn-add {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: 6px;
    box-shadow: var(--shadow-sm);
}

.btn-add:hover { background-color: var(--primary-hover); transform: translateY(-1px); }
.btn-add:active { transform: translateY(0); }

.header-stats {
    display: flex;
    gap: 12px;
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 500;
    overflow: hidden;
    white-space: nowrap;
    flex: 1;
    min-width: 0;
    margin-right: 12px;
}

.header-stats span { display: flex; align-items: center; gap: 6px; }
.stat-dot { width: 8px; height: 8px; border-radius: 50%; }
.dot-all { background: var(--text-muted); }
.dot-todo { background: #3b82f6; }
.dot-prog { background: var(--pri-med); }
.dot-done { background: var(--success); }

/* --- BOARD --- */
.board {
    display: flex;
    flex-direction: column;
    gap: 16px;
    padding: 16px;
    overflow-y: auto;
    flex: 1;
}

.column {
    background-color: transparent;
    border-radius: var(--radius-lg);
    display: flex;
    flex-direction: column;
}

@media (min-width: 768px) {
    .board {
        flex-direction: row;
        justify-content: center;
        margin: 0 auto;
        max-width: 1400px;
        width: 100%;
        overflow-x: auto;
        overflow-y: hidden;
        gap: 20px;
        padding: 24px;
    }
    .column {
        flex: 1;
        min-width: 300px;
        max-width: 400px;
        height: 100%;
    }
    .column .task-list {
        overflow-y: auto;
    }
}

.col-header {
    padding: 12px 16px;
    font-weight: 600;
    font-size: 13px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: #ffffff;
    background: var(--text-main);
    border-radius: var(--radius-sm);
    margin: 0 0 12px 0;
}

.col-count {
    background: rgba(255, 255, 255, 0.2);
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 12px;
    color: #ffffff;
    font-weight: 600;
}

.col-header svg.icon { stroke: #ffffff !important; }

.task-list {
    flex: 1;
    padding: 0 16px 16px 16px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
    transition: background 0.2s;
}

.task-list.drag-over {
    background-color: rgba(15, 23, 42, 0.03);
    border-radius: var(--radius-lg);
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: 24px 16px;
    color: var(--text-light);
    font-size: 13px;
    font-weight: 500;
    border: 1px dashed var(--border-hover);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s;
}

.empty-state:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: rgba(15, 23, 42, 0.02);
}

/* --- CARD --- */
.card {
    background-color: var(--card-bg);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    border-left: 4px solid var(--border);
    padding: 16px;
    box-shadow: var(--shadow-sm);
    cursor: grab;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    user-select: none;
    -webkit-user-select: none;
    -webkit-touch-callout: none;
    touch-action: manipulation;
}

.card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.card:active { cursor: grabbing; }

.card.dragging {
    opacity: 0.8;
    transform: scale(1.02) rotate(2deg);
    box-shadow: var(--shadow-float);
    z-index: 100;
}

/* SortableJS */
.sortable-ghost { opacity: 0.4; }
.sortable-chosen { cursor: grabbing; }

/* Priority border colors */
.border-pri-low { border-left-color: var(--pri-low); }
.border-pri-medium { border-left-color: var(--pri-med); }
.border-pri-high { border-left-color: var(--pri-high); }
.border-pri-critical { border-left-color: var(--pri-crit); }

.card-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

/* Priority badge */
.card-priority-badge {
    font-size: 11px;
    padding: 4px 8px;
    border-radius: 6px;
    font-weight: 600;
    letter-spacing: 0.02em;
    white-space: nowrap;
    flex-shrink: 0;
}
.badge-low { background-color: #dcfce3; color: #16a34a; }
.badge-medium { background-color: #fef08a; color: #ca8a04; }
.badge-high { background-color: #ffedd5; color: #ea580c; }
.badge-critical { background-color: #fee2e2; color: #dc2626; }

/* Priority dot (view modal) */
.card-priority {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    flex-shrink: 0;
}
.pri-low { background-color: var(--pri-low); }
.pri-medium { background-color: var(--pri-med); }
.pri-high { background-color: var(--pri-high); }
.pri-critical { background-color: var(--pri-crit); }

.card-tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    justify-content: flex-end;
    flex: 1;
    margin-left: 12px;
}

.tag {
    font-size: 11px;
    padding: 4px 8px;
    border-radius: 6px;
    background: #f1f5f9;
    color: #475569;
    font-weight: 500;
    letter-spacing: 0.02em;
    border: 1px solid rgba(0,0,0,0.03);
}
.tag.blue { background: #eff6ff; color: #2563eb; border-color: #dbeafe; }
.tag.purple { background: #faf5ff; color: #9333ea; border-color: #f3e8ff; }
.tag.green { background: #f0fdf4; color: #16a34a; border-color: #dcfce3; }
.tag.orange { background: #fff7ed; color: #ea580c; border-color: #fed7aa; }
.tag.red { background: #fef2f2; color: #dc2626; border-color: #fecaca; }

.card-title {
    font-size: 15px;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 6px;
    word-break: break-word;
    color: var(--text-main);
}

.card-desc {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.5;
    margin-bottom: 16px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid var(--border);
    padding-top: 12px;
}

.card-assignee {
    display: flex;
    align-items: center;
    gap: 8px;
}

.assignee-avatar {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: #e2e8f0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 600;
    color: #475569;
}

.assignee-name {
    font-size: 13px;
    color: var(--text-muted);
    font-weight: 500;
}

.card-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 12px;
    color: var(--text-light);
    font-weight: 500;
}

.card-deadline { display: flex; align-items: center; gap: 4px; }
.card-deadline.overdue { color: var(--danger); }
.card-deadline svg { width: 14px; height: 14px; }

.card-stats { display: flex; gap: 10px; }
.card-stat { display: flex; align-items: center; gap: 4px; }
.card-stat svg { width: 14px; height: 14px; color: var(--text-light); }

/* --- DONE COLUMN STYLES --- */
#list-done .card {
    background-color: #f8fafc;
    border-color: var(--border);
    border-left-color: #cbd5e1;
    box-shadow: none;
}

#list-done .card:hover {
    transform: translateY(-2px);
    background-color: #ffffff;
    border-left-color: #94a3b8;
    box-shadow: var(--shadow-sm);
}

#list-done .card-title {
    color: var(--text-muted);
    font-weight: 500;
}

#list-done .card-desc {
    color: var(--text-light);
}

#list-done .card-priority-badge {
    background-color: #f1f5f9;
    color: #94a3b8;
}

#list-done .tag {
    background-color: transparent;
    border-color: var(--border);
    color: var(--text-light);
}

#list-done .assignee-avatar {
    filter: grayscale(100%);
    opacity: 0.6;
}

#list-done .card-deadline.overdue {
    color: var(--text-light);
}

/* --- MODALS (BOTTOM SHEETS) --- */
.modal-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(15, 23, 42, 0.4);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 100;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.modal-overlay.active { opacity: 1; pointer-events: auto; }

.modal-content {
    background: var(--card-bg);
    border-radius: 24px 24px 0 0;
    padding: 32px 24px 24px 24px;
    width: 100%;
    max-height: 92vh;
    overflow-y: auto;
    transform: translateY(100%);
    transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    position: relative;
    box-shadow: var(--shadow-float);
}

@media (min-width: 600px) {
    .modal-overlay { justify-content: center; align-items: center; padding: 20px; }
    .modal-content {
        border-radius: var(--radius-lg);
        width: 100%;
        max-width: 540px;
        transform: scale(0.95) translateY(20px);
        opacity: 0;
        padding: 32px;
    }
    .modal-overlay.active .modal-content { transform: scale(1) translateY(0); opacity: 1; }
}

.modal-overlay.active .modal-content { transform: translateY(0); }

.modal-drag-handle {
    width: 48px;
    height: 5px;
    background: #cbd5e1;
    border-radius: 3px;
    position: absolute;
    top: 12px;
    left: 50%;
    transform: translateX(-50%);
}
@media (min-width: 600px) { .modal-drag-handle { display: none; } }

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 24px;
}

.modal-title { font-size: 20px; font-weight: 700; letter-spacing: -0.02em; color: var(--text-main); }

.btn-close {
    background: #f1f5f9;
    border: none;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text-muted);
    transition: all 0.2s;
    flex-shrink: 0;
}
.btn-close:hover { background: #e2e8f0; color: var(--text-main); }

/* Forms */
.form-group { margin-bottom: 20px; }
.form-label { display: block; font-size: 13px; font-weight: 600; margin-bottom: 8px; color: var(--text-muted); }

.form-input, .form-select, .form-textarea {
    width: 100%;
    padding: 12px 16px;
    background: #f8fafc;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-family: 'Inter', sans-serif;
    font-size: 15px;
    color: var(--text-main);
    outline: none;
    transition: all 0.2s;
}
.form-input:focus, .form-select:focus, .form-textarea:focus {
    background: #ffffff;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(15, 23, 42, 0.1);
}
.form-textarea { resize: vertical; min-height: 100px; line-height: 1.5; }

.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    padding-right: 40px;
}

.priority-selector { display: flex; gap: 12px; }
.pri-btn {
    flex: 1; padding: 10px; border-radius: var(--radius-sm); border: 1px solid var(--border);
    background: #f8fafc; cursor: pointer; display: flex; align-items: center; justify-content: center; gap: 8px;
    font-size: 13px; font-weight: 500; transition: all 0.2s; color: var(--text-muted);
}
.pri-btn:hover { border-color: var(--border-hover); background: #ffffff; }
.pri-btn.selected { border-color: var(--primary); background: #ffffff; color: var(--text-main); box-shadow: 0 1px 2px rgba(0,0,0,0.05); }
.pri-btn .dot { width: 8px; height: 8px; border-radius: 50%; }

/* Tag selector (pill toggle buttons in create modal) */
.tags-selector {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tag-btn {
    padding: 6px 14px;
    border-radius: 20px;
    border: 1px solid var(--border);
    background: #f8fafc;
    color: var(--text-muted);
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    font-family: 'Inter', sans-serif;
}
.tag-btn:hover { border-color: var(--border-hover); background: #ffffff; }
.tag-btn.active {
    background: var(--primary);
    color: #ffffff;
    border-color: var(--primary);
}

.modal-actions { display: flex; gap: 12px; margin-top: 24px; }
.btn { flex: 1; padding: 12px 16px; border-radius: var(--radius-sm); font-size: 15px; font-weight: 600; cursor: pointer; border: none; transition: all 0.2s; }
.btn-cancel { background: #f1f5f9; color: var(--text-main); border: 1px solid transparent; }
.btn-cancel:hover { background: #e2e8f0; }
.btn-save { background: var(--primary); color: white; box-shadow: 0 1px 3px rgba(15, 23, 42, 0.2); }
.btn-save:hover { background: var(--primary-hover); }

/* View Modal */
.view-tags { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 20px; }
.view-desc {
    font-size: 15px; line-height: 1.6; color: var(--text-main); margin-bottom: 32px;
    background: #f8fafc; padding: 16px 20px; border-radius: var(--radius-sm); border: 1px solid var(--border);
}

.view-meta-grid {
    display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-bottom: 32px;
    background: #ffffff; border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 12px;
}

@media (max-width: 400px) {
    .view-meta-grid { grid-template-columns: 1fr; }
}
.meta-item { display: flex; flex-direction: column; gap: 6px; min-width: 0; }
.meta-item .form-input, .meta-item .form-select { width: 100%; box-sizing: border-box; font-size: 13px; padding: 8px 10px; }
.meta-item input[type="date"] { width: auto; }
.meta-label { font-size: 12px; color: var(--text-muted); font-weight: 500; }
.meta-value { font-size: 14px; font-weight: 600; display: flex; align-items: center; gap: 8px; color: var(--text-main); }

.section-title {
    font-size: 16px; font-weight: 600; margin-bottom: 20px; color: var(--text-main);
    display: flex; align-items: center; gap: 8px;
}
.section-title::before {
    content: ''; display: block; width: 4px; height: 16px;
    background: var(--border-hover); border-radius: 2px;
}

.comments-list {
    display: flex; flex-direction: column; gap: 20px; margin-bottom: 24px;
    max-height: 250px; overflow-y: auto; padding-right: 8px;
}
.comment { display: flex; gap: 12px; }
.comment-avatar {
    width: 36px; height: 36px; border-radius: 50%; background: #e2e8f0;
    flex-shrink: 0; display: flex; align-items: center; justify-content: center;
    font-size: 13px; font-weight: 600; color: #475569;
}
.comment-content { flex: 1; }
.comment-header { display: flex; align-items: center; gap: 12px; margin-bottom: 4px; }
.comment-author { font-size: 14px; font-weight: 600; color: var(--text-main); }
.comment-time { font-size: 12px; color: var(--text-light); }
.comment-text {
    font-size: 14px; line-height: 1.5; color: var(--text-main);
    background: #f8fafc; padding: 12px 16px; border-radius: 0 12px 12px 12px;
    border: 1px solid var(--border); display: inline-block;
}

.add-comment {
    display: flex; gap: 12px; align-items: flex-end;
    border-top: 1px solid var(--border); padding-top: 24px;
}
.add-comment .form-input {
    margin-bottom: 0; flex: 1; border-radius: 24px; padding: 12px 20px; background: #ffffff;
}
.btn-send {
    background: var(--primary); color: white; border: none; width: 44px; height: 44px;
    border-radius: 50%; cursor: pointer; display: flex; align-items: center; justify-content: center;
    transition: all 0.2s; flex-shrink: 0;
}
.btn-send:hover { background: var(--primary-hover); transform: scale(1.05); }

.view-actions { display: flex; gap: 12px; margin-top: 32px; border-top: 1px solid var(--border); padding-top: 24px; }
.btn-delete { background: #fff; color: var(--danger); border: 1px solid #fca5a5; }
.btn-delete:hover { background: #fef2f2; }
.btn-edit { background: #f1f5f9; color: var(--text-main); border: 1px solid transparent; }
.btn-edit:hover { background: #e2e8f0; }

/* SVG icon utility */
.icon { stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; fill: none; }

/* Confetti (CSS fallback) */
.confetti-container {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    pointer-events: none;
    z-index: 9999;
    overflow: hidden;
}

.confetti-piece {
    position: absolute;
    animation: confetti-fall 2s ease-in forwards;
}

@keyframes confetti-fall {
    0% { transform: translateY(0) rotate(0deg); opacity: 1; }
    100% { transform: translateY(100vh) rotate(720deg); opacity: 0; }
}