/* Thinka-style CSS for Free Practice System */

/* App Layout */
.app-layout {
    display: flex;
    min-height: 100vh;
    background: var(--bg-primary);
}

/* Sidebar */
.sidebar {
    width: 240px;
    background: var(--bg-secondary);
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--border);
    position: fixed;
    height: 100vh;
    overflow-y: auto;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--border);
}

.sidebar-header .logo {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #f59e0b, #d97706);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 15px;
    font-size: 1.8em;
    color: white;
}

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

.user-name {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.user-email {
    font-size: 0.85em;
    color: var(--text-secondary);
}

.nav-menu {
    list-style: none;
    padding: 15px 0;
    flex: 1;
}

.nav-item {
    margin: 4px 10px;
}

.nav-item a {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 15px;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 8px;
    transition: all 0.2s ease;
}

.nav-item a:hover {
    background: var(--bg-card);
    color: var(--text-primary);
}

.nav-item.active a {
    background: var(--primary);
    color: white;
}

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

.sidebar-footer {
    padding: 15px;
    border-top: 1px solid var(--border);
}

.btn-logout {
    width: 100%;
    padding: 10px;
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: all 0.2s ease;
}

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

.version {
    text-align: center;
    font-size: 0.75em;
    color: var(--text-secondary);
    margin-top: 10px;
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: 240px;
    padding: 30px;
    max-width: 1200px;
}

.page-header {
    margin-bottom: 30px;
}

.page-header h1 {
    font-size: 1.8em;
    color: var(--primary);
    margin-bottom: 15px;
}

.header-tabs {
    display: flex;
    gap: 10px;
}

.tab-btn {
    padding: 10px 20px;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: all 0.2s ease;
}

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

/* Config Section */
.config-section {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 25px;
    margin-bottom: 25px;
}

.config-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 20px;
}

.config-row:last-child {
    margin-bottom: 0;
}

.config-item label {
    display: block;
    font-size: 0.9em;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.config-item select,
.config-item input {
    width: 100%;
    padding: 10px 15px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1em;
}

.config-item select:focus,
.config-item input:focus {
    outline: none;
    border-color: var(--primary);
}

/* Difficulty Stars */
.difficulty-stars {
    display: flex;
    gap: 5px;
    padding: 10px 0;
}

.difficulty-stars .star {
    font-size: 1.5em;
    color: var(--border);
    cursor: pointer;
    transition: color 0.2s ease;
}

.difficulty-stars .star.active {
    color: var(--warning);
}

.difficulty-stars .star:hover {
    color: var(--warning);
}

/* Topics Section */
.topics-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin-bottom: 25px;
}

.topic-card {
    background: var(--bg-secondary);
    border-radius: 12px;
    overflow: hidden;
}

.topic-header {
    padding: 15px 20px;
    background: var(--bg-card);
    border-left: 4px solid var(--topic-color, var(--primary));
    font-weight: 600;
    color: var(--text-primary);
}

.topic-subtopics {
    padding: 15px 20px;
}

.subtopic-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 0;
    cursor: pointer;
    color: var(--text-secondary);
    transition: color 0.2s ease;
}

.subtopic-item:hover {
    color: var(--text-primary);
}

.subtopic-item input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--primary);
}

/* Action Section */
.action-section {
    text-align: center;
    padding: 20px 0;
}

.btn-start {
    padding: 15px 60px;
    font-size: 1.1em;
    font-weight: 600;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn-start:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.4);
}

.btn-start i {
    margin-right: 10px;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.loading-content {
    text-align: center;
    color: white;
}

.loading-content i {
    font-size: 3em;
    margin-bottom: 20px;
}

/* Working Page Styles */
.working-header {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 15px 20px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
}

.working-header .back-btn {
    background: none;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    font-size: 1.2em;
}

.working-header h1 {
    font-size: 1.3em;
    color: var(--text-primary);
}

.timer-display {
    margin-left: auto;
    font-size: 1.3em;
    font-weight: 600;
    color: var(--text-primary);
}

.progress-bar {
    height: 4px;
    background: var(--success);
    transition: width 0.5s linear;
}

/* Question Area */
.question-area {
    display: flex;
    gap: 20px;
    padding: 30px;
    min-height: calc(100vh - 100px);
}

.question-content {
    flex: 1;
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 25px;
}

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

.question-number {
    font-size: 1.3em;
    font-weight: 600;
    color: var(--text-primary);
}

.question-actions {
    display: flex;
    gap: 10px;
}

.question-actions button {
    background: var(--bg-card);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 8px 12px;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.question-actions button:hover {
    color: var(--text-primary);
    border-color: var(--primary);
}

.question-actions button.active {
    background: var(--warning);
    border-color: var(--warning);
    color: white;
}

.question-score {
    color: var(--text-secondary);
    font-size: 0.9em;
}

.question-text {
    font-size: 1.1em;
    line-height: 1.7;
    color: var(--text-primary);
    margin-bottom: 25px;
}

/* MC Options */
.mc-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.mc-option {
    padding: 15px 20px;
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: flex-start;
    gap: 12px;
}

.mc-option:hover {
    border-color: var(--primary);
}

.mc-option.selected {
    border-color: var(--primary);
    background: rgba(37, 99, 235, 0.1);
}

.mc-option.correct {
    border-color: var(--success);
    background: rgba(34, 197, 94, 0.1);
}

.mc-option.incorrect {
    border-color: var(--danger);
    background: rgba(239, 68, 68, 0.1);
}

.mc-option .option-letter {
    font-weight: 600;
    color: var(--primary);
}

.mc-option .option-text {
    flex: 1;
    color: var(--text-primary);
}

/* Short/Long Answer Input */
.answer-input-section {
    margin-top: 20px;
}

.answer-input-section h3 {
    color: var(--text-secondary);
    font-size: 0.95em;
    margin-bottom: 15px;
}

.input-tools {
    display: flex;
    gap: 15px;
    margin-bottom: 15px;
    flex-wrap: wrap;
}

.input-tool {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 0.9em;
    transition: all 0.2s ease;
}

.input-tool:hover {
    color: var(--primary);
    border-color: var(--primary);
}

.answer-textarea {
    width: 100%;
    min-height: 200px;
    padding: 15px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1em;
    line-height: 1.6;
    resize: vertical;
}

.answer-textarea:focus {
    outline: none;
    border-color: var(--primary);
}

/* Question Navigation */
.question-nav {
    width: 80px;
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 15px;
}

.nav-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.nav-item-btn {
    width: 50px;
    height: 40px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text-secondary);
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s ease;
}

.nav-item-btn:hover {
    border-color: var(--primary);
}

.nav-item-btn.current {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

.nav-item-btn.answered {
    background: var(--success);
    border-color: var(--success);
    color: white;
}

.nav-item-btn.flagged {
    border-color: var(--warning);
    box-shadow: inset 0 0 0 2px var(--warning);
}

/* Navigation Buttons */
.nav-buttons {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
}

.btn-nav {
    padding: 12px 30px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-nav:hover {
    color: var(--text-primary);
    border-color: var(--primary);
}

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

.btn-submit {
    padding: 12px 40px;
    background: var(--primary);
    border: none;
    color: white;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.2s ease;
}

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

/* Statistics Page */
.stats-filters {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 25px;
    flex-wrap: wrap;
}

.period-buttons {
    display: flex;
    gap: 5px;
}

.period-btn {
    padding: 8px 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

.date-range {
    display: flex;
    align-items: center;
    gap: 10px;
}

.date-range input {
    padding: 8px 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text-primary);
}

/* Stats Cards */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 25px;
    text-align: center;
}

.stat-card .stat-label {
    color: var(--primary);
    font-size: 0.9em;
    margin-bottom: 10px;
}

.stat-card .stat-value {
    font-size: 2em;
    font-weight: 700;
    color: var(--text-primary);
}

.stat-card .stat-value.grade {
    color: var(--warning);
}

.stat-card .stat-value.grade-u {
    color: var(--danger);
}

/* Chart Container */
.chart-container {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 25px;
    margin-bottom: 25px;
}

.chart-container h3 {
    color: var(--text-primary);
    margin-bottom: 20px;
}

/* History Table */
.history-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-secondary);
    border-radius: 12px;
    overflow: hidden;
}

.history-table th,
.history-table td {
    padding: 15px 20px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.history-table th {
    background: var(--bg-card);
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9em;
}

.history-table td {
    color: var(--text-primary);
}

.history-table tr:hover td {
    background: var(--bg-card);
}

.grade-badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 4px;
    font-weight: 600;
    font-size: 0.9em;
}

.grade-badge.grade-5ss {
    background: #fef3c7;
    color: #d97706;
}

.grade-badge.grade-5s {
    background: #dcfce7;
    color: #16a34a;
}

.grade-badge.grade-5 {
    background: #dbeafe;
    color: #2563eb;
}

.grade-badge.grade-4 {
    background: #e0e7ff;
    color: #4f46e5;
}

.grade-badge.grade-3 {
    background: #f3e8ff;
    color: #9333ea;
}

.grade-badge.grade-2 {
    background: #fce7f3;
    color: #db2777;
}

.grade-badge.grade-1 {
    background: #fee2e2;
    color: #dc2626;
}

.grade-badge.grade-u {
    background: #fee2e2;
    color: #dc2626;
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        width: 60px;
    }

    .sidebar-header .logo {
        width: 40px;
        height: 40px;
        font-size: 1.2em;
    }

    .user-info,
    .nav-item span,
    .btn-logout span {
        display: none;
    }

    .nav-item a {
        justify-content: center;
        padding: 15px;
    }

    .main-content {
        margin-left: 60px;
        padding: 20px;
    }

    .mc-options {
        grid-template-columns: 1fr;
    }

    .question-nav {
        display: none;
    }
}