/* =======================
   UTC2 Grammar Page Styles
   Modern, Professional, Responsive
   ======================= */

/* Import Poppins font is in HTML head */

* {
    box-sizing: border-box;
}

/* Only apply Poppins to specific grammar content, not body/menu */
.grammar-main-container,
.grammar-hero-section,
.grammar-search-section,
.grammar-card,
.grammar-detail-panel {
    font-family: 'Poppins', Arial, sans-serif;
}

/* Hero Section */
.grammar-hero-section {
    background: linear-gradient(135deg, #1f767a 0%, #20b2aa 50%, #106468 100%);
    padding: 80px 20px 60px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.grammar-hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><circle cx="50" cy="50" r="2" fill="rgba(255,255,255,0.1)"/></svg>');
    opacity: 0.3;
}

.grammar-hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    margin: 0 auto;
}

.grammar-hero-title {
    font-size: 4rem;
    font-weight: 700;
    color: #ffffff;
    margin-bottom: 20px;
    text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.2);
    letter-spacing: 2px;
}

.grammar-hero-subtitle {
    font-size: 1.25rem;
    font-weight: 400;
    color: rgba(255, 255, 255, 0.95);
    line-height: 1.6;
    max-width: 600px;
    margin: 0 auto;
}

/* Search and Filter Section */
.grammar-search-section {
    background: #ffffff;
    padding: 40px 20px 30px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    margin-top: 20px;
}

.grammar-search-wrapper {
    max-width: 1200px;
    margin: 0 auto;
}

.grammar-search-bar {
    display: flex;
    align-items: center;
    gap: 12px;
    background: #f8f9fa;
    border: 2px solid #e0e0e0;
    border-radius: 30px;
    padding: 12px 20px;
    margin-bottom: 20px;
    transition: all 0.3s ease;
}

.grammar-search-bar:focus-within {
    border-color: #106468;
    box-shadow: 0 0 0 3px rgba(16, 100, 104, 0.1);
}

.grammar-search-bar i {
    color: #106468;
    font-size: 18px;
}

.grammar-search-input {
    flex: 1;
    border: none;
    outline: none;
    background: transparent;
    font-size: 16px;
    font-family: 'Poppins', sans-serif;
    color: #1d2a57;
}

.grammar-search-input::placeholder {
    color: #9ca3af;
}

.grammar-search-btn {
    background: linear-gradient(135deg, #106468 0%, #1d2a57 100%);
    color: #ffffff;
    border: none;
    padding: 10px 24px;
    border-radius: 25px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'Poppins', sans-serif;
}

.grammar-search-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(16, 100, 104, 0.3);
}

.grammar-filter-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

.grammar-filter-chip {
    padding: 10px 20px;
    border: 2px solid #106468;
    background: #ffffff;
    color: #106468;
    border-radius: 25px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'Poppins', sans-serif;
}

.grammar-filter-chip:hover {
    background: #f0f8f9;
    transform: translateY(-2px);
}

.grammar-filter-chip.active {
    background: linear-gradient(135deg, #106468 0%, #1d2a57 100%);
    color: #ffffff;
    box-shadow: 0 4px 12px rgba(16, 100, 104, 0.3);
}

/* Main Container */
.grammar-main-container {
    max-width: 1400px;
    margin: 40px auto 80px;
    padding: 0 20px;
}

.grammar-content-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    align-items: start;
}

/* Grammar Cards Column */
.grammar-cards-column {
    min-height: 400px;
}

.grammar-cards-grid {
    display: grid;
    gap: 20px;
}

.grammar-card {
    background: #ffffff;
    border: 2px solid #e0e0e0;
    border-radius: 16px;
    padding: 24px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.grammar-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
    border-color: #106468;
}

.grammar-card.active {
    border-color: #106468;
    background: linear-gradient(135deg, #f0f8f9 0%, #e0f7f8 100%);
    box-shadow: 0 8px 24px rgba(16, 100, 104, 0.2);
}

.grammar-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 12px;
}

.grammar-card-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: #1d2a57;
    margin: 0;
}

.grammar-card-tag {
    display: inline-block;
    padding: 4px 12px;
    background: linear-gradient(135deg, #106468 0%, #1d2a57 100%);
    color: #ffffff;
    border-radius: 12px;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.grammar-card-description {
    font-size: 14px;
    color: #626a8a;
    line-height: 1.6;
    margin: 0;
}

.grammar-card.hidden {
    display: none;
}

/* Detail Panel */
.grammar-detail-column {
    position: sticky;
    top: 100px;
    max-height: calc(100vh - 120px);
    overflow-y: auto;
}

.grammar-detail-panel {
    background: #ffffff;
    border: 2px solid #e0e0e0;
    border-radius: 16px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
    overflow: hidden;
}

.grammar-detail-placeholder {
    padding: 60px 40px;
    text-align: center;
    color: #9ca3af;
}

.grammar-detail-placeholder i {
    font-size: 4rem;
    margin-bottom: 20px;
    color: #d1d5db;
}

.grammar-detail-placeholder p {
    font-size: 16px;
    margin: 0;
}

/* Detail Panel Content */
.grammar-detail-header {
    background: linear-gradient(135deg, #106468 0%, #1d2a57 100%);
    color: #ffffff;
    padding: 24px;
}

.grammar-detail-title {
    font-size: 1.75rem;
    font-weight: 600;
    margin: 0 0 8px 0;
}

.grammar-detail-tag {
    display: inline-block;
    padding: 4px 12px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
}

.grammar-detail-tabs {
    display: flex;
    border-bottom: 2px solid #e0e0e0;
    background: #f8f9fa;
}

.grammar-tab-btn {
    flex: 1;
    padding: 16px;
    border: none;
    background: transparent;
    font-size: 15px;
    font-weight: 500;
    color: #626a8a;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'Poppins', sans-serif;
    border-bottom: 3px solid transparent;
}

.grammar-tab-btn:hover {
    background: #f0f8f9;
    color: #106468;
}

.grammar-tab-btn.active {
    color: #106468;
    border-bottom-color: #106468;
    background: #ffffff;
}

.grammar-tab-content {
    display: none;
    padding: 24px;
}

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

.grammar-explanation-section {
    margin-bottom: 24px;
}

.grammar-section-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1d2a57;
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 2px solid #e0e0e0;
}

.grammar-section-text {
    font-size: 15px;
    color: #1d2a57;
    line-height: 1.8;
    margin-bottom: 16px;
}

.grammar-structure-box {
    background: #f0f8f9;
    border-left: 4px solid #106468;
    padding: 16px;
    border-radius: 8px;
    margin: 16px 0;
}

.grammar-structure-box code {
    font-family: 'Courier New', monospace;
    font-size: 14px;
    color: #1d2a57;
    background: transparent;
}

.grammar-examples-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.grammar-example-item {
    padding: 12px 0;
    border-bottom: 1px solid #e0e0e0;
}

.grammar-example-item:last-child {
    border-bottom: none;
}

.grammar-example-en {
    font-size: 15px;
    color: #1d2a57;
    font-style: italic;
    margin-bottom: 4px;
}

.grammar-example-vi {
    font-size: 14px;
    color: #106468;
    font-weight: 500;
}

.grammar-mistakes-box {
    background: #fff3cd;
    border-left: 4px solid #ffc107;
    padding: 16px;
    border-radius: 8px;
    margin-top: 16px;
}

.grammar-mistakes-box .grammar-section-title {
    color: #856404;
    border-bottom-color: #ffc107;
}

.grammar-mistakes-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.grammar-mistakes-list li {
    padding: 8px 0;
    color: #856404;
    font-size: 14px;
}

.grammar-mistakes-list li::before {
    content: '⚠ ';
    margin-right: 8px;
}

/* Quiz Section */
.grammar-quiz-container {
    max-width: 100%;
}

.grammar-quiz-question {
    margin-bottom: 24px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 12px;
    border: 2px solid #e0e0e0;
}

.grammar-quiz-question.correct {
    border-color: #28a745;
    background: #d4edda;
}

.grammar-quiz-question.incorrect {
    border-color: #dc3545;
    background: #f8d7da;
}

.grammar-quiz-question-title {
    font-size: 16px;
    font-weight: 600;
    color: #1d2a57;
    margin-bottom: 12px;
}

.grammar-quiz-options {
    list-style: none;
    padding: 0;
    margin: 0;
}

.grammar-quiz-option {
    padding: 12px;
    margin-bottom: 8px;
    background: #ffffff;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.grammar-quiz-option:hover {
    border-color: #106468;
    background: #f0f8f9;
}

.grammar-quiz-option input[type="radio"] {
    margin-right: 10px;
    cursor: pointer;
}

.grammar-quiz-option.correct-answer {
    background: #d4edda;
    border-color: #28a745;
    color: #155724;
}

.grammar-quiz-option.wrong-answer {
    background: #f8d7da;
    border-color: #dc3545;
    color: #721c24;
}

.grammar-quiz-submit {
    background: linear-gradient(135deg, #106468 0%, #1d2a57 100%);
    color: #ffffff;
    border: none;
    padding: 14px 32px;
    border-radius: 25px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'Poppins', sans-serif;
    width: 100%;
    margin-top: 20px;
}

.grammar-quiz-submit:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(16, 100, 104, 0.3);
}

.grammar-quiz-result {
    margin-top: 20px;
    padding: 20px;
    background: linear-gradient(135deg, #106468 0%, #1d2a57 100%);
    color: #ffffff;
    border-radius: 12px;
    text-align: center;
    display: none;
}

.grammar-quiz-result.show {
    display: block;
}

.grammar-quiz-score {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.grammar-quiz-message {
    font-size: 16px;
    margin: 0;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .grammar-content-wrapper {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .grammar-detail-column {
        position: static;
        max-height: none;
    }
}

@media (max-width: 768px) {
    .grammar-hero-title {
        font-size: 2.5rem;
    }

    .grammar-hero-subtitle {
        font-size: 1.1rem;
    }

    .grammar-search-bar {
        flex-wrap: wrap;
    }

    .grammar-search-btn {
        width: 100%;
        margin-top: 8px;
    }

    .grammar-filter-chips {
        gap: 8px;
    }

    .grammar-filter-chip {
        padding: 8px 16px;
        font-size: 13px;
    }

    .grammar-card-title {
        font-size: 1.25rem;
    }

    .grammar-detail-title {
        font-size: 1.5rem;
    }

    .grammar-tabs {
        flex-direction: column;
    }

    .grammar-tab-btn {
        border-bottom: none;
        border-left: 3px solid transparent;
    }

    .grammar-tab-btn.active {
        border-left-color: #106468;
        border-bottom-color: transparent;
    }
}

@media (max-width: 480px) {
    .grammar-hero-section {
        padding: 60px 15px 40px;
    }

    .grammar-hero-title {
        font-size: 2rem;
    }

    .grammar-hero-subtitle {
        font-size: 1rem;
    }

    .grammar-search-section {
        padding: 20px 15px;
    }

    .grammar-main-container {
        margin: 30px auto 60px;
        padding: 0 15px;
    }

    .grammar-card {
        padding: 20px;
    }

    .grammar-detail-header {
        padding: 20px;
    }

    .grammar-tab-content {
        padding: 20px;
    }
}