:root {
    --bg-color: #f3f4f6;
    --sidebar-bg: #ffffff;
    --text-color: #333333;
    --border-color: #e5e7eb;
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --danger-color: #ef4444;
    --modal-bg: #ffffff;
    --input-bg: #ffffff;
}

body.dark-mode {
    --bg-color: #111827;
    --sidebar-bg: #1f2937;
    --text-color: #f9fafb;
    --border-color: #374151;
    --primary-color: #3b82f6;
    --primary-hover: #60a5fa;
    --danger-color: #ef4444;
    --modal-bg: #1f2937;
    --input-bg: #374151;
    
    /* FullCalendar Dark Theme Overrides */
    --fc-page-bg-color: var(--bg-color);
    --fc-neutral-bg-color: var(--sidebar-bg);
    --fc-neutral-text-color: var(--text-color);
    --fc-border-color: var(--border-color);
    --fc-button-text-color: #fff;
    --fc-button-bg-color: #374151;
    --fc-button-border-color: #4b5563;
    --fc-button-hover-bg-color: #4b5563;
    --fc-button-hover-border-color: #6b7280;
    --fc-button-active-bg-color: #4b5563;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
}

.app-container {
    display: flex;
    height: 100vh;
    padding: 20px;
    gap: 20px;
}

/* Sidebar Styles */
.sidebar {
    width: 250px;
    background-color: var(--sidebar-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 10px;
}

.sidebar h2 {
    font-size: 1.2rem;
    margin: 0;
}

.category-list {
    flex-grow: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.category-item-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 4px 0;
}

.category-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.95rem;
    cursor: pointer;
    flex-grow: 1;
}

.delete-cat-btn {
    color: #9ca3af;
    cursor: pointer;
    font-size: 1.2rem;
    line-height: 1;
    padding: 0 4px;
    visibility: hidden;
}
.delete-cat-btn:hover {
    color: var(--danger-color);
}
.category-item-wrapper:hover .delete-cat-btn {
    visibility: visible;
}

.add-category-box {
    margin-top: 20px;
    display: flex;
    align-items: center;
    background-color: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 2px 4px 2px 8px;
}

.add-category-box input {
    flex-grow: 1;
    border: none;
    background: transparent;
    padding: 8px 0;
    outline: none;
    font-size: 0.9rem;
}

.add-category-box button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 4px;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-weight: bold;
    font-size: 1.2rem;
    transition: background-color 0.2s;
}

.add-category-box button:hover {
    background-color: var(--primary-hover);
}

/* Search Box Styles */
.search-box {
    margin-bottom: 5px;
}

.search-box input {
    width: 100%;
    border: 1px solid var(--border-color);
    background-color: var(--input-bg);
    color: var(--text-color);
    padding: 8px 10px;
    border-radius: 6px;
    outline: none;
    font-size: 0.95rem;
    transition: border-color 0.2s;
}

.search-box input:focus {
    border-color: var(--primary-color);
}

/* FullCalendar Weekend and Holiday Colors */
.fc-day-sun .fc-daygrid-day-number,
.fc-day-sun .fc-col-header-cell-cushion {
    color: #ef4444 !important; /* Red */
}

.fc-day-sat .fc-daygrid-day-number,
.fc-day-sat .fc-col-header-cell-cushion {
    color: #3b82f6 !important; /* Blue */
}

.holiday-red .fc-daygrid-day-number {
    color: #ef4444 !important;
}

.fc-icon-theme-toggle::before {
    content: "🌙";
    font-family: sans-serif;
    font-size: 1.2rem;
    font-style: normal;
}
body.dark-mode .fc-icon-theme-toggle::before {
    content: "☀️";
}

/* Calendar Styles */
.calendar-container {
    flex-grow: 1;
    background-color: var(--sidebar-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    overflow: hidden; /* prevents scrollbars if fullcalendar sizes perfectly */
}

/* === Event Hover & Color Styles === */
.fc-event {
    cursor: pointer;
    transition: transform 0.15s ease, box-shadow 0.15s ease, filter 0.15s ease;
    border-left-width: 4px !important;
    border-radius: 4px !important;
}

.fc-event:hover {
    transform: translateY(-2px) scale(1.02);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
    filter: brightness(0.95);
    z-index: 10 !important;
}

/* 텍스트가 테두리에 너무 붙지 않도록 좌측 여백 추가 (스페이스바 2칸 정도) */
.fc-event .fc-event-main {
    padding-left: 12px !important;
}

.fc-event .fc-event-main,
.fc-event .fc-event-title,
.fc-event .fc-event-time {
    color: var(--text-color) !important;
    font-weight: 600;
    /* 그라데이션 배경(오른쪽이 짙어짐)에서도 글씨가 뚜렷하게 보이도록 그림자 추가 */
    text-shadow: 0 1px 3px rgba(255, 255, 255, 0.9);
}

body.dark-mode .fc-event .fc-event-main,
body.dark-mode .fc-event .fc-event-title,
body.dark-mode .fc-event .fc-event-time {
    color: var(--text-color) !important;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.9);
}

/* Modal Styles */
.modal {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background-color: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background-color: var(--modal-bg);
    padding: 25px;
    border-radius: 8px;
    width: 400px;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.close-btn {
    font-size: 1.5rem;
    cursor: pointer;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
    font-size: 0.9rem;
}

.form-group input[type="text"],
.form-group input[type="date"],
.form-group select,
.form-group input[type="color"] {
    width: 100%;
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: var(--input-bg);
    color: var(--text-color);
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: 25px;
}

.btn {
    padding: 8px 16px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: bold;
}

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

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

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

/* Color Picker Styles */
.color-picker-container {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 5px;
}
.color-btn {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: 2px solid transparent;
    cursor: pointer;
    padding: 0;
}
.color-btn.selected {
    border-color: var(--text-color);
    transform: scale(1.1);
}

.add-category-box input {
    color: var(--text-color);
}

/* === Responsive Layout (Mobile Optimization) === */
@media (max-width: 768px) {
    .app-container {
        flex-direction: column;
        padding: 10px;
        gap: 10px;
        height: auto;
        min-height: 100vh;
    }

    .sidebar {
        width: 100%;
        border-radius: 8px;
        padding: 15px;
    }
    
    .sidebar-header {
        margin-bottom: 10px;
        padding-bottom: 5px;
    }

    /* 모바일에서는 카테고리들을 가로로 눕히고 둥근 버튼(Pill) 형태로 만들어 터치 친화적으로 변경 */
    .category-list {
        flex-direction: row;
        flex-wrap: wrap;
        gap: 8px;
    }

    .category-item-wrapper {
        background-color: var(--input-bg);
        border: 1px solid var(--border-color);
        border-radius: 20px;
        padding: 6px 12px;
    }

    .calendar-container {
        border-radius: 8px;
        height: 600px; /* min-height 대신 명시적 height 부여 (달력 내부 붕괴 방지) */
        padding: 10px;
    }

    /* FullCalendar 상단 툴바가 모바일에서 겹치지 않도록 세로 정렬 */
    .fc-header-toolbar {
        flex-direction: column !important;
        gap: 12px;
    }

    .fc-toolbar-chunk {
        display: flex;
        justify-content: center;
        width: 100%;
    }

    /* 모바일 달력 내부 글씨 크기 조정 */
    .fc-event .fc-event-title {
        font-size: 0.75rem;
    }
    .fc-toolbar-title {
        font-size: 1.25rem !important;
    }

    .modal-content {
        width: 95%;
        padding: 20px;
    }
}