:root {
    /* Color Palette - Modern Light Theme */
    --color-bg-body: #F4F6F8;
    --color-bg-panel: #FFFFFF;
    --color-text-main: #2C3E50;
    --color-text-muted: #7F8C8D;

    --color-primary: #3498DB;
    --color-primary-hover: #2980B9;
    --color-danger: #E74C3C;
    --color-danger-hover: #C0392B;

    --color-border: #E8ECEF;
    --color-border-dark: #D1D8DD;

    /* Task Colors */
    --color-task-major: rgba(167, 219, 169, 0.4);
    --color-task-major-border: #8ec390;
    --color-task-uncompleted: #64C5ED;
    --color-task-completed: #BDBDBD;

    /* Layout Variables */
    --sidebar-width: 420px;
    --header-height: 70px;
    --gantt-row-height: 40px;

    /* Spacing & Shadows */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;

    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.03);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 12px 24px rgba(0, 0, 0, 0.1);

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
}

/* Reset & Base */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Noto Sans JP', sans-serif;
    background-color: var(--color-bg-body);
    color: var(--color-text-main);
    line-height: 1.5;
    font-size: 14px;
    overflow: hidden;
    /* Prevent body scroll, layout uses internal scroll */
}

/* Typography */
h1,
h2,
h3 {
    font-weight: 500;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    outline: none;
}

.btn:disabled {
    cursor: not-allowed;
    opacity: 0.5;
}

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

.btn-primary:not(:disabled):hover {
    background-color: var(--color-primary-hover);
}

.btn-outline {
    background-color: transparent;
    border: 1px solid var(--color-border-dark);
    color: var(--color-text-main);
}

.btn-outline:not(:disabled):hover {
    background-color: var(--color-bg-body);
}

.btn-text {
    background-color: transparent;
    color: var(--color-text-muted);
}

.btn-text:not(:disabled):hover {
    color: var(--color-text-main);
    background-color: var(--color-bg-body);
}

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

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

/* Form Inputs */
.form-input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 14px;
    transition: border-color 0.2s;
}

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

select.form-input,
select#project-selector {
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%237F8C8D' 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 12px center;
    background-size: 16px;
    padding-right: 32px;
}

/* Layout */
.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    width: 100vw;
}

.app-header {
    height: auto;
    background-color: var(--color-bg-panel);
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    padding: var(--spacing-md) var(--spacing-xl);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
    z-index: 10;
    gap: var(--spacing-sm);
}

.header-main {
    width: 100%;
}

.header-sub {
    width: 100%;
}

.app-title {
    font-size: 18px;
    letter-spacing: 0.5px;
    font-weight: 700;
    color: var(--color-text-main);
}

.progress-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.current-project-name {
    font-weight: 700;
    color: var(--color-primary);
    font-size: 14px;
    background-color: rgba(52, 152, 219, 0.05);
    padding: 2px 8px;
    border-radius: 4px;
    margin-right: 4px;
}

.progress-label {
    font-size: 13px;
    color: var(--color-text-muted);
}

.progress-bar-wrap {
    width: 250px;
    height: 8px;
    background-color: var(--color-bg-body);
    border-radius: 4px;
    overflow: hidden;
}

.progress-bar-inner {
    height: 100%;
    background-color: var(--color-primary);
    width: 0%;
    transition: width 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.progress-text {
    font-weight: 500;
    width: 40px;
    text-align: right;
}

/* Main Area */
.app-main {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* Left Panel: Task List */
.task-panel {
    width: var(--sidebar-width);
    background-color: var(--color-bg-panel);
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--color-border);
    z-index: 5;
    flex-shrink: 0;
}

.panel-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.project-selector-wrap {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

#project-selector {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border-dark);
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 15px;
    background-color: #FAFAFA;
}

.task-list-container {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-md);
}

.panel-footer {
    padding: var(--spacing-md) var(--spacing-lg);
    border-top: 1px solid var(--color-border);
    background-color: var(--color-bg-panel);
}

.panel-footer .btn {
    width: 100%;
}

/* Task Items styling */
.major-task-item {
    background-color: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    margin-bottom: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.major-task-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md);
    background-color: #FAFAFA;
    border-bottom: 1px solid var(--color-border);
    cursor: pointer;
    user-select: none;
}

.major-task-title-wrap {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.major-task-title {
    font-weight: 500;
    font-size: 15px;
}

.major-task-progress {
    font-size: 12px;
    color: var(--color-primary);
    background-color: rgba(52, 152, 219, 0.1);
    padding: 2px 6px;
    border-radius: 12px;
    font-weight: 500;
}

.major-task-actions {
    display: flex;
    gap: var(--spacing-xs);
}

.icon-btn {
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 4px;
    color: var(--color-text-muted);
    border-radius: 4px;
    transition: all 0.2s;
}

.icon-btn:hover {
    background-color: var(--color-border);
    color: var(--color-text-main);
}

.icon-btn.danger:hover {
    color: var(--color-danger);
}

/* Drag and Drop */
.drag-handle {
    cursor: grab;
    color: var(--color-text-muted);
    padding: 0 4px;
    font-size: 18px;
    user-select: none;
    display: flex;
    align-items: center;
}

.drag-handle:active {
    cursor: grabbing;
}

.drag-handle.small {
    font-size: 14px;
    padding-right: 8px;
}

.major-task-item.dragging,
.detail-task-item.dragging {
    opacity: 0.4;
    background-color: var(--color-bg-body);
}

.major-task-item.drag-over {
    border: 2px dashed var(--color-primary);
}

.detail-task-item.drag-over {
    background-color: rgba(52, 152, 219, 0.05);
    border-top: 2px solid var(--color-primary);
}

/* Detail Task List */
.detail-task-list {
    padding: 0;
    list-style: none;
}

.detail-task-item {
    display: flex;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
    gap: var(--spacing-sm);
    transition: background-color 0.2s;
    height: var(--gantt-row-height);
}

.detail-task-item:last-child {
    border-bottom: none;
}

.detail-task-item:hover {
    background-color: var(--color-bg-body);
}

.detail-task-checkbox {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--color-primary);
}

.detail-task-name {
    flex: 1;
    font-size: 13px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.detail-task-item.completed .detail-task-name {
    color: var(--color-text-muted);
    text-decoration: line-through;
}

.detail-task-dates {
    font-size: 11px;
    color: var(--color-text-muted);
    white-space: nowrap;
}

.major-task-add-detail {
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: #fff;
}

.major-task-add-detail .btn {
    width: 100%;
    font-size: 12px;
    padding: 6px;
}

/* Right Panel: Gantt Chart */
.gantt-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    /* Scroll logic is inside */
    background-color: #FAFAFA;
    position: relative;
}

.gantt-header {
    height: 50px;
    border-bottom: 1px solid var(--color-border);
    background-color: var(--color-bg-panel);
    display: flex;
    overflow: hidden;
    /* Synced scroll with body */
    position: sticky;
    top: 0;
    z-index: 2;
}

.gantt-header-date {
    flex-shrink: 0;
    border-right: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    color: var(--color-text-muted);
    user-select: none;
}

.gantt-header-date .day {
    font-weight: 500;
    color: var(--color-text-main);
    font-size: 13px;
}

.gantt-header-date.weekend {
    background-color: rgba(0, 0, 0, 0.02);
    color: #E74C3C;
}

.gantt-body {
    flex: 1;
    overflow: auto;
    /* Both X and Y scroll */
    position: relative;
    background-image: linear-gradient(to right, var(--color-border) 1px, transparent 1px);
}

.gantt-grid {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    pointer-events: none;
    /* Grid lines drawn dynamically via rects or background-size in JS */
}

.gantt-bars {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
}

/* Gantt Chart Rows */
.gantt-row {
    height: var(--gantt-row-height);
    position: relative;
    border-bottom: 1px dashed var(--color-border);
    display: flex;
    align-items: center;
}

.gantt-row.major-row {
    background-color: rgba(0, 0, 0, 0.01);
    height: 53px;
    /* approximate to match major task header */
}

/* Row Drag Handle */
.gantt-row-drag-handle {
    position: sticky;
    left: 0;
    width: 30px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #EEE;
    /* 視認性のために少し濃く */
    border-right: 1px solid var(--color-border);
    cursor: grab;
    color: var(--color-text-muted);
    z-index: 100;
    /* 最前面に */
    user-select: none;
    font-size: 18px;
    flex-shrink: 0;
}

.gantt-row-drag-handle:active {
    cursor: grabbing;
}

.gantt-row-drag-handle.small {
    font-size: 12px;
}

.gantt-row.dragging {
    opacity: 0.4;
}

.gantt-row.drag-over {
    border-top: 2px solid var(--color-primary);
    background-color: rgba(52, 152, 219, 0.05);
}

/* Gantt Chart Bars */
.gantt-bar-wrap {
    position: absolute;
    top: 0;
    height: 100%;
    display: flex;
    align-items: center;
}

.gantt-bar {
    height: 24px;
    border-radius: 4px;
    position: relative;
    box-shadow: var(--shadow-sm);
    min-width: 10px;
    transition: background-color 0.3s;
}

.gantt-bar.major {
    background-color: var(--color-task-major);
    border: 1px solid var(--color-task-major-border);
    height: 16px;
    border-radius: 8px;
    pointer-events: none;
}

.gantt-bar.detail {
    background-color: var(--color-task-uncompleted);
    cursor: grab;
}

.gantt-bar.detail:active {
    cursor: grabbing;
}

.gantt-bar.detail.completed {
    background-color: var(--color-task-completed);
}

.gantt-bar-handle {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 10px;
    cursor: ew-resize;
    z-index: 2;
}

.gantt-bar-handle.left {
    left: 0;
}

.gantt-bar-handle.right {
    right: 0;
}

.gantt-bar-label {
    display: none;
    /* app.jsで削除済みですが、念のため非表示 */
}

.gantt-bar-info {
    position: absolute;
    left: 4px;
    top: -2.5px;
    /* バー内の上部に配置 */
    display: flex;
    align-items: center;
    gap: 4px;
    pointer-events: none;
    z-index: 3;
    white-space: nowrap;
}

.gantt-bar-name {
    font-size: 7px;
    font-weight: 500;
    color: var(--color-text-main);
}

.gantt-bar-date {
    font-size: 7px;
    color: var(--color-text-muted);
}

.major-row .gantt-bar-info {
    top: 1px;
}

/* Scrollbars styling for webkit */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: #CDD5DB;
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: #A0B1BC;
}

/* Modals */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 1;
    transition: opacity 0.2s;
    backdrop-filter: blur(2px);
}

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

.modal {
    background-color: var(--color-bg-panel);
    border-radius: var(--radius-md);
    width: 90%;
    max-width: 500px;
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    transform: translateY(0);
    transition: transform 0.2s;
}

.modal-overlay.hidden .modal {
    transform: translateY(20px);
}

.modal.modal-sm {
    max-width: 360px;
}

.modal-title {
    padding: var(--spacing-lg) var(--spacing-lg) var(--spacing-md);
    font-size: 18px;
    font-weight: 700;
    border-bottom: 1px solid var(--color-border);
}

.modal-body {
    padding: var(--spacing-lg);
}

.modal-footer {
    padding: var(--spacing-md) var(--spacing-lg);
    background-color: #FAFAFA;
    display: flex;
    justify-content: flex-end;
    gap: var(--spacing-md);
    border-top: 1px solid var(--color-border);
}

.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-size: 13px;
    font-weight: 500;
    color: var(--color-text-muted);
}

.form-row {
    display: flex;
    gap: var(--spacing-md);
}

.form-row .form-group {
    flex: 1;
}

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

/* ========================================
   モバイル用タブナビゲーション
   ======================================== */
.mobile-tabs {
    display: none;
    /* デフォルトはPC表示のため非表示 */
}

/* ========================================
   レスポンシブ対応 (768px以下)
   ======================================== */
@media (max-width: 768px) {

    /* ヘッダー */
    .app-header {
        height: auto;
        padding: var(--spacing-sm) var(--spacing-md);
        flex-wrap: wrap;
        gap: var(--spacing-sm);
    }

    .app-title {
        font-size: 15px;
    }

    .progress-container {
        flex: 1;
        gap: var(--spacing-sm);
    }

    .progress-label {
        display: none;
        /* 狭い画面では非表示 */
    }

    .progress-bar-wrap {
        width: 120px;
    }

    /* モバイルタブ */
    .mobile-tabs {
        display: flex;
        background-color: var(--color-bg-panel);
        border-bottom: 1px solid var(--color-border);
        flex-shrink: 0;
    }

    .mobile-tab {
        flex: 1;
        padding: 10px;
        font-size: 13px;
        font-family: inherit;
        font-weight: 500;
        border: none;
        border-bottom: 3px solid transparent;
        background: transparent;
        color: var(--color-text-muted);
        cursor: pointer;
        transition: all 0.2s;
    }

    .mobile-tab.active {
        color: var(--color-primary);
        border-bottom-color: var(--color-primary);
    }

    /* メインエリア：縦並びに切り替え */
    .app-main {
        flex-direction: column;
        overflow: hidden;
    }

    /* タスクパネル：モバイルでは全幅、縦スクロール */
    .task-panel {
        width: 100%;
        height: 100%;
        border-right: none;
        border-bottom: 1px solid var(--color-border);
        flex-shrink: 0;
        display: flex;
        flex-direction: column;
    }

    /* タブによる表示切り替え */
    .task-panel.mobile-hidden,
    .gantt-panel.mobile-hidden {
        display: none;
    }

    /* パネルヘッダー */
    .panel-header {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    /* プロジェクトセレクター */
    .project-selector-wrap {
        flex-direction: row;
        align-items: center;
        gap: var(--spacing-sm);
    }

    #project-selector {
        flex: 1;
        font-size: 13px;
        padding: var(--spacing-xs) var(--spacing-sm);
    }

    #btn-new-project {
        font-size: 12px;
        padding: var(--spacing-xs) var(--spacing-sm);
        white-space: nowrap;
    }

    /* 詳細タスクのUI拡大（タップしやすく） */
    .detail-task-item {
        padding: var(--spacing-sm) var(--spacing-sm);
        height: auto;
        min-height: var(--gantt-row-height);
    }

    .detail-task-checkbox {
        width: 20px;
        height: 20px;
    }

    .detail-task-dates {
        display: none;
        /* 狭い画面では省スペース化 */
    }

    .icon-btn {
        padding: 6px;
        font-size: 15px;
    }

    /* パネルフッター */
    .panel-footer {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    /* ガントパネル */
    .gantt-panel {
        flex: 1;
        min-height: 0;
    }

    /* ガントチャートのバーの操作感向上（タッチ） */
    .gantt-bar-handle {
        width: 16px;
        /* タッチしやすい幅に */
    }

    /* モーダル */
    .modal {
        max-width: calc(100% - 32px);
    }
}