:root {
    --primary-color: #5b5bff;
    --primary-hover: #4a4aff;
    --primary-light: #f0f0ff;
    --secondary-color: #00d4ff;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-tertiary: #9ca3af;
    --border-color: #e5e7eb;
    --border-light: #f3f4f6;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Helvetica Neue', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

html, body {
    height: 100%;
    width: 100%;
}

/* 로그인 페이지 */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-box {
    background: white;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 400px;
}

.login-box h1 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--text-primary);
    font-size: 24px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-secondary);
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 14px;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
}

.btn-login {
    width: 100%;
    padding: 12px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s;
}

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

.error-message {
    color: #dc3545;
    text-align: center;
    margin-top: 15px;
    font-size: 14px;
}

/* 메인 레이아웃 */
.app-container {
    display: flex;
    height: 100vh;
    flex-direction: column;
}

/* 헤더 */
.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    box-shadow: var(--shadow-md);
    padding: 16px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-shrink: 0;
    position: relative;
    z-index: 100;
}

.logo {
    font-size: 26px;
    font-weight: 700;
    color: white;
    letter-spacing: -0.5px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo::before {
    content: '';
    width: 4px;
    height: 24px;
    background: linear-gradient(180deg, var(--secondary-color), var(--primary-light));
    border-radius: 2px;
}

.header-right {
    display: flex;
    gap: 20px;
    align-items: center;
}

.user-info {
    color: rgba(255, 255, 255, 0.95);
    font-size: 14px;
    font-weight: 500;
}

.user-info strong {
    font-weight: 700;
    margin-left: 4px;
}

.btn-logout {
    padding: 8px 16px;
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 6px;
    cursor: pointer;
    font-size: 13px;
    font-weight: 600;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.btn-logout:hover {
    background-color: rgba(255, 255, 255, 0.3);
    border-color: rgba(255, 255, 255, 0.5);
    transform: translateY(-1px);
}

/* 콘텐츠 영역 */
.content {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* 왼쪽 사이드바 */
.sidebar {
    width: 240px;
    background-color: var(--bg-primary);
    border-right: 1px solid var(--border-color);
    overflow-y: auto;
    padding: 20px 0;
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
}

.sidebar-title {
    padding: 12px 20px;
    font-size: 11px;
    font-weight: 700;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-top: 8px;
}

.sidebar-item {
    padding: 10px 20px;
    cursor: pointer;
    transition: all 0.2s ease;
    color: var(--text-secondary);
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 500;
    margin: 0 8px;
    border-radius: 8px;
    border-left: 3px solid transparent;
}

.sidebar-item:hover {
    background-color: var(--primary-light);
    color: var(--primary-color);
}

.sidebar-item.active {
    background-color: var(--primary-light);
    color: var(--primary-color);
    font-weight: 600;
    border-left-color: var(--primary-color);
}

.sidebar-item i {
    width: 20px;
    text-align: center;
}

/* 메인 콘텐츠 */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* 도구모음 */
.toolbar {
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: 16px 24px;
    display: flex;
    gap: 12px;
    align-items: center;
    flex-wrap: wrap;
    flex-shrink: 0;
}

.btn-group {
    display: flex;
    gap: 8px;
}

.btn {
    padding: 10px 16px;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 6px;
    white-space: nowrap;
}

.btn:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--border-light);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.btn.primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    border: none;
    box-shadow: var(--shadow-sm);
}

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

.breadcrumb {
    display: flex;
    gap: 4px;
    align-items: center;
    margin-left: auto;
    font-size: 13px;
}

.breadcrumb-item {
    cursor: pointer;
    color: var(--primary-color);
    padding: 6px 10px;
    border-radius: 6px;
    transition: all 0.2s ease;
    font-weight: 500;
}

.breadcrumb-item:hover {
    background-color: var(--primary-light);
}

.breadcrumb-separator {
    color: var(--border-color);
    margin: 0 2px;
}

/* 파일 브라우저 */
.file-browser {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    background-color: var(--bg-primary);
}

.file-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
    gap: 16px;
    padding: 4px;
}

.file-item {
    background-color: var(--bg-primary);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 16px;
    text-align: center;
    cursor: pointer;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    user-select: none;
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.file-item:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
    transform: translateY(-4px);
    background: linear-gradient(135deg, var(--primary-light) 0%, var(--bg-primary) 100%);
}

.file-item.selected {
    background: linear-gradient(135deg, var(--primary-light) 0%, var(--bg-secondary) 100%);
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(91, 91, 255, 0.1);
}

.file-icon {
    font-size: 52px;
    line-height: 1;
}

.file-name {
    font-size: 13px;
    color: var(--text-primary);
    word-break: break-word;
    white-space: normal;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

.file-size {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 5px;
}

/* 파일 리스트 뷰 */
.file-list {
    background-color: var(--bg-primary);
    border-radius: 12px;
    overflow: hidden;
    margin: 4px;
    border: 1px solid var(--border-color);
}

.file-list-header {
    display: grid;
    grid-template-columns: 40px 1fr 100px 100px 150px 50px;
    gap: 15px;
    padding: 14px 20px;
    background-color: var(--bg-secondary);
    font-weight: 600;
    font-size: 12px;
    color: var(--text-tertiary);
    border-bottom: 1px solid var(--border-color);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.file-list-item {
    display: grid;
    grid-template-columns: 40px 1fr 100px 100px 150px 50px;
    gap: 15px;
    padding: 14px 20px;
    align-items: center;
    border-bottom: 1px solid var(--border-light);
    transition: all 0.15s ease;
}

.file-list-item:hover {
    background-color: var(--bg-secondary);
}

.file-list-item.selected {
    background-color: var(--primary-light);
}

.checkbox {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.file-list-name {
    display: flex;
    align-items: center;
    gap: 10px;
    overflow: hidden;
}

.file-list-icon {
    font-size: 24px;
    flex-shrink: 0;
}

.file-list-text {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: var(--text-primary);
    font-size: 14px;
}

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

.file-list-size, .file-list-date {
    font-size: 13px;
    color: var(--text-secondary);
}

/* 드래그 앤 드롭 영역 */
.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 48px 32px;
    text-align: center;
    margin: 24px;
    transition: all 0.2s ease;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
}

.drop-zone.active {
    border-color: var(--primary-color);
    background: linear-gradient(135deg, var(--primary-light) 0%, rgba(0, 212, 255, 0.05) 100%);
}

.drop-zone-icon {
    font-size: 56px;
    margin-bottom: 16px;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-8px); }
}

.drop-zone-text {
    font-size: 16px;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.drop-zone-hint {
    font-size: 13px;
    color: var(--text-secondary);
}

/* 업로드 진행 */
.upload-progress {
    position: fixed;
    bottom: 24px;
    right: 24px;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 18px;
    max-width: 320px;
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    backdrop-filter: blur(10px);
}

.upload-item {
    margin-bottom: 12px;
}

.upload-name {
    font-size: 13px;
    color: var(--text-primary);
    margin-bottom: 6px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-weight: 500;
}

.progress-bar {
    width: 100%;
    height: 6px;
    background-color: var(--bg-tertiary);
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    width: 0%;
    transition: width 0.3s ease;
    border-radius: 3px;
}

/* 컨텍스트 메뉴 */
.context-menu {
    position: fixed;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    box-shadow: var(--shadow-lg);
    z-index: 2000;
    min-width: 200px;
    overflow: hidden;
}

.context-menu-item {
    padding: 12px 16px;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-primary);
    transition: all 0.15s ease;
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 500;
}

.context-menu-item:hover {
    background-color: var(--primary-light);
    color: var(--primary-color);
}

.context-menu-divider {
    height: 1px;
    background-color: var(--border-color);
    margin: 4px 0;
}

.context-menu-danger {
    color: var(--danger-color);
}

.context-menu-danger:hover {
    background-color: rgba(239, 68, 68, 0.1);
    color: var(--danger-color);
}

/* 모달 */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(4px);
}

.modal.active {
    display: flex;
    justify-content: center;
    align-items: center;
}

.modal-content {
    background-color: var(--bg-primary);
    padding: 32px;
    border-radius: 16px;
    max-width: 500px;
    width: 90%;
    box-shadow: var(--shadow-xl);
    animation: slideUp 0.3s ease-out;
}

@keyframes slideUp {
    from {
        transform: translateY(20px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.modal-header {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.modal-body {
    margin-bottom: 24px;
}

.modal-footer {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
}

/* 버튼 그룹 */
.btn-group-full {
    display: flex;
    gap: 10px;
}

.btn-group-full .btn {
    flex: 1;
}

/* 빈 상태 */
.empty-state {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100%;
    color: var(--text-secondary);
}

.empty-icon {
    font-size: 72px;
    margin-bottom: 20px;
    opacity: 0.8;
}

.empty-text {
    font-size: 18px;
    margin-bottom: 10px;
    color: var(--text-primary);
    font-weight: 600;
}

.empty-hint {
    font-size: 14px;
    color: var(--text-tertiary);
}

/* 로딩 스피너 */
.spinner {
    border: 3px solid var(--bg-tertiary);
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    width: 32px;
    height: 32px;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 스크롤바 스타일 */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-tertiary);
}

/* 반응형 */
@media (max-width: 768px) {
    .sidebar {
        display: none;
    }

    .content {
        flex-direction: column;
    }

    .file-grid {
        grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
    }

    .file-list-header, .file-list-item {
        grid-template-columns: 1fr 80px;
    }

    .toolbar {
        flex-direction: column;
        align-items: stretch;
    }

    .breadcrumb {
        margin-left: 0;
        margin-top: 10px;
    }
}

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

.text-center {
    text-align: center;
}

.text-muted {
    color: var(--text-secondary);
}

.mt-20 {
    margin-top: 20px;
}

.mb-20 {
    margin-bottom: 20px;
}

.p-20 {
    padding: 20px;
}