:root {
    --primary-color: #1e3a8a;
    --primary-hover: #1e40af;
    --bg-color: #ffffff;
    --sidebar-bg: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #1e293b;
    --text-sub: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(30, 58, 138, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(30, 58, 138, 0.1), 0 2px 4px -1px rgba(30, 58, 138, 0.06);
    --glass-bg: rgba(248, 250, 252, 0.85);
    --glass-border: rgba(30, 58, 138, 0.1);
}

[data-theme="dark"] {
    --primary-color: #60a5fa;
    --primary-hover: #93c5fd;
    --bg-color: #0a1929;
    --sidebar-bg: #1e293b;
    --card-bg: #1e293b;
    --text-main: #f8fafc;
    --text-sub: #94a3b8;
    --border-color: #334155;
    --shadow-sm: 0 1px 2px 0 rgba(96, 165, 250, 0.1);
    --shadow-md: 0 4px 6px -1px rgba(96, 165, 250, 0.15), 0 2px 4px -1px rgba(96, 165, 250, 0.1);
    --glass-bg: rgba(30, 41, 59, 0.9);
    --glass-border: rgba(96, 165, 250, 0.15);
}

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

body {
    font-family: 'Noto Sans KR', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    height: 100vh;
    overflow: hidden;
    transition: background-color 0.3s, color 0.3s;
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100%;
}

/* Header */
.app-header {
    height: 60px;
    background-color: var(--sidebar-bg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
    box-shadow: var(--shadow-sm);
    z-index: 10;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--primary-color);
}

.logo-area h1 {
    font-size: 1.2rem;
    font-weight: 700;
}

.controls {
    display: flex;
    gap: 10px;
}

.file-upload-btn {
    background-color: var(--primary-color);
    color: white;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.2s;
    display: flex;
    align-items: center;
    gap: 8px;
}

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

.icon-btn {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-main);
    width: 36px;
    height: 36px;
    border-radius: 6px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

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

/* Main Layout */
.main-content {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* Sidebar */
.sidebar {
    width: 300px;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.filter-box {
    padding: 10px 15px 0 15px;
    display: flex;
    gap: 5px;
}

.filter-box select {
    flex: 1;
    padding: 6px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--bg-color);
    color: var(--text-main);
    font-size: 0.9rem;
    outline: none;
}

.search-box {
    padding: 15px;
    border-bottom: 1px solid var(--border-color);
    position: relative;
}

.search-box i {
    position: absolute;
    left: 25px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-sub);
}

.search-box input {
    width: 100%;
    padding: 8px 10px 8px 35px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--bg-color);
    color: var(--text-main);
    outline: none;
}

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

.student-list {
    flex: 1;
    overflow-y: auto;
    padding: 10px;
}

.student-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
}

.student-table th {
    background-color: var(--bg-color);
    padding: 8px 4px;
    text-align: center;
    font-weight: 600;
    color: var(--text-sub);
    border-bottom: 2px solid var(--border-color);
    position: sticky;
    top: 0;
    font-size: 0.8rem;
}

.student-table td {
    padding: 10px 6px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-main);
}

.student-table tbody tr {
    cursor: pointer;
    transition: background-color 0.2s;
}

.student-table tbody tr:hover {
    background-color: var(--bg-color);
}

.student-table tbody tr.active {
    background-color: var(--primary-color);
    color: white;
}

.student-table tbody tr.active td {
    color: white;
}

.empty-state {
    text-align: center;
    padding: 20px;
    color: var(--text-sub);
}

/* Content Area */
.content-area {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    background-color: var(--bg-color);
}

.welcome-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--text-sub);
    text-align: center;
}

.welcome-screen i {
    font-size: 4rem;
    margin-bottom: 20px;
    color: var(--border-color);
}

/* Student Detail View */
.student-header {
    margin-bottom: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.student-info {
    display: flex;
    align-items: center;
    gap: 15px;
}

.student-name {
    font-size: 1.5rem;
    font-weight: 700;
}

.badge {
    background-color: var(--primary-color);
    color: white;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.9rem;
}

.tabs {
    display: flex;
    gap: 10px;
    background-color: var(--sidebar-bg);
    padding: 5px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.tab-btn {
    padding: 8px 16px;
    border: none;
    background: none;
    cursor: pointer;
    border-radius: 6px;
    color: var(--text-sub);
    font-weight: 500;
    transition: all 0.2s;
}

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

.tab-content {
    display: none;
    animation: fadeIn 0.3s ease;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Split View & Editor */
.split-view {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    height: calc(100vh - 180px); /* Adjust based on header/padding */
}

.activity-list-section, .editor-section {
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
}

.full-width {
    grid-column: 1 / -1;
}

.activity-list-section h3, .editor-section h3 {
    margin-bottom: 15px;
    font-size: 1.1rem;
    color: var(--text-main);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 10px;
}

.activity-list {
    flex: 1;
    overflow-y: auto;
    padding-right: 5px;
}

.activity-card {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 10px;
    transition: transform 0.2s;
}

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

.activity-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-size: 0.9rem;
    color: var(--primary-color);
    font-weight: 600;
}

.activity-content {
    font-size: 0.95rem;
    line-height: 1.5;
    color: var(--text-main);
    white-space: pre-wrap;
}

.activity-actions {
    margin-top: 10px;
    display: flex;
    justify-content: flex-end;
}

.sm-btn {
    padding: 4px 8px;
    font-size: 0.8rem;
    border: 1px solid var(--border-color);
    background-color: var(--sidebar-bg);
    border-radius: 4px;
    cursor: pointer;
    color: var(--text-sub);
}

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

/* Editor */
.editor-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.byte-counter {
    font-size: 0.9rem;
    color: var(--text-sub);
    font-variant-numeric: tabular-nums;
}

.action-btn {
    padding: 6px 12px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background-color: var(--sidebar-bg);
    cursor: pointer;
    color: var(--text-main);
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.action-btn.primary {
    background-color: var(--primary-color);
    color: white;
    border: none;
}

.summary-editor {
    flex: 1;
    width: 100%;
    resize: none;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 15px;
    font-family: 'Noto Sans KR', sans-serif;
    font-size: 1rem;
    line-height: 1.6;
    background-color: var(--bg-color);
    color: var(--text-main);
    outline: none;
}

.summary-editor:focus {
    border-color: var(--primary-color);
    background-color: var(--sidebar-bg);
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--text-sub);
}

/* Volunteer Table */
.volunteer-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.volunteer-table th {
    background-color: var(--bg-color);
    padding: 10px;
    text-align: left;
    font-weight: 600;
    color: var(--text-sub);
    border-bottom: 2px solid var(--border-color);
}

.volunteer-table td {
    padding: 12px 10px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-main);
    vertical-align: top;
}

.volunteer-table tr:hover {
    background-color: var(--bg-color);
}

.content-cell {
    white-space: pre-wrap;
    line-height: 1.5;
}

.icon-only-btn {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-sub);
    padding: 5px;
    border-radius: 4px;
    transition: all 0.2s;
}

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

/* Logo & Footer */
.app-logo {
    height: 32px;
    width: auto;
}

.app-footer {
    height: 40px;
    background-color: var(--sidebar-bg);
    border-top: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    color: var(--text-sub);
}