/* --- HỆ THỐNG CSS CHUẨN PREMIUM CHO HỆ THỐNG KHẢO SÁT TIẾNG ANH --- */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&display=swap');

:root {
    --bg-main: #090d16;
    --bg-header: #0e1322;
    --bg-card: #141b2d;
    --bg-card-hover: #1c263e;
    --bg-input: #0b0f19;
    --border-color: #1e2942;
    --border-glow: rgba(59, 130, 246, 0.15);
    
    --text-main: #f3f4f6;
    --text-muted: #94a3b8;
    --text-dark: #64748b;
    
    --color-primary: #3b82f6;
    --color-primary-hover: #2563eb;
    --color-primary-rgb: 59, 130, 246;
    
    --color-reading: #14b8a6;
    --color-reading-bg: rgba(20, 184, 166, 0.1);
    --color-reading-border: rgba(20, 184, 166, 0.25);
    
    --color-listening: #84cc16;
    --color-listening-bg: rgba(132, 204, 22, 0.1);
    --color-listening-border: rgba(132, 204, 22, 0.25);
    
    --color-speaking: #0ea5e9;
    --color-speaking-bg: rgba(14, 165, 233, 0.1);
    --color-speaking-border: rgba(14, 165, 233, 0.25);
    
    --color-writing: #10b981;
    --color-writing-bg: rgba(16, 185, 129, 0.1);
    --color-writing-border: rgba(16, 185, 129, 0.25);

    --color-danger: #f43f5e;
    --color-warning: #f59e0b;
    --color-success: #10b981;
}

/* Base resets & typography */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    user-select: none; /* Khóa copy để bảo mật đề thi */
    overflow-x: hidden;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

/* Glassmorphism & premium UI containers */
.glass-panel {
    background: rgba(20, 27, 45, 0.7);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

.glow-card {
    position: relative;
    overflow: hidden;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.glow-card:hover {
    transform: translateY(-2px);
    border-color: var(--color-primary);
    box-shadow: 0 0 15px var(--border-glow);
}

/* Scrollbar styling */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: var(--bg-main);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

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

/* Custom Text Size adjustments */
.font-size-small {
    font-size: 0.85rem !important;
}
.font-size-medium {
    font-size: 1rem !important;
}
.font-size-large {
    font-size: 1.2rem !important;
}

/* Header style modifications */
header {
    background: var(--bg-header);
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

/* Custom Sidebar navigation */
aside {
    background: var(--bg-header);
    border-right: 1px solid var(--border-color);
}

.timeline-line {
    width: 2px;
    background-color: var(--border-color);
    position: absolute;
    top: 24px;
    bottom: -12px;
    left: 19px;
}

.timeline-line-active {
    background-color: var(--color-primary);
}

.sidebar-node {
    transition: all 0.3s ease;
}

/* Custom Buttons with smooth gradients */
.btn-grad {
    background: linear-gradient(135deg, var(--color-primary) 0%, #1d4ed8 100%);
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
    transition: all 0.3s ease;
}

.btn-grad:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.45);
    filter: brightness(1.1);
}

.btn-danger-grad {
    background: linear-gradient(135deg, var(--color-danger) 0%, #b91c1c 100%);
    box-shadow: 0 4px 15px rgba(244, 63, 94, 0.3);
    transition: all 0.3s ease;
}

.btn-danger-grad:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(244, 63, 94, 0.45);
    filter: brightness(1.1);
}

/* Audio Player styles (Listening hardware & media tests) */
.custom-audio-bar {
    position: relative;
    border-radius: 0.75rem;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

/* Active speaking recording countdown ring */
.ring-container {
    position: relative;
    width: 150px;
    height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.ring-svg {
    transform: rotate(-90deg);
    position: absolute;
}

.ring-circle {
    transition: stroke-dashoffset 0.1s linear;
}

/* Bilingual translations elements with glow effects */
.bilingual-translation-box {
    margin-top: 0.5rem;
    padding: 0.75rem 1rem;
    background-color: rgba(59, 130, 246, 0.05);
    border-left: 3px solid var(--color-primary);
    border-radius: 0 0.5rem 0.5rem 0;
    font-size: 0.85em;
    color: #a5f3fc;
    animation: slideDown 0.3s ease-out forwards;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-5px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Bilingual toggle translation buttons */
.btn-translate-toggle {
    background: rgba(59, 130, 246, 0.1);
    color: var(--color-primary);
    border: 1px solid rgba(59, 130, 246, 0.2);
    border-radius: 0.375rem;
    padding: 0.25rem 0.5rem;
    font-size: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    transition: all 0.2s ease;
}

.btn-translate-toggle:hover {
    background: rgba(59, 130, 246, 0.2);
    transform: scale(1.03);
}

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

/* Switch styling for general answers toggle */
.switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #334155;
    transition: .4s;
    border-radius: 24px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked + .slider {
    background-color: var(--color-primary);
}

input:focus + .slider {
    box-shadow: 0 0 1px var(--color-primary);
}

input:checked + .slider:before {
    transform: translateX(20px);
}

/* Results comparisons bars for CEFR / IELTS / VSTEP */
.compare-bar-segment {
    flex: 1;
    min-width: 0;
    height: 100%;
    transition: all 0.4s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 8.5px;
    font-weight: 800;
    color: var(--text-dark);
    border-right: 1px solid var(--bg-main);
    white-space: nowrap;
    text-overflow: ellipsis;
    overflow: hidden;
    padding: 0 2px;
}

.compare-bar-segment.active-cefr {
    background-color: var(--color-reading);
    color: #ffffff;
    font-size: 10.5px;
    font-weight: 900;
    box-shadow: 0 0 12px rgba(20, 184, 166, 0.6);
    overflow: visible;
}

.compare-bar-segment.active-ielts {
    background-color: var(--color-speaking);
    color: #ffffff;
    font-size: 10.5px;
    font-weight: 900;
    box-shadow: 0 0 12px rgba(14, 165, 233, 0.6);
    overflow: visible;
}

.compare-bar-segment.active-vstep {
    background-color: var(--color-writing);
    color: #ffffff;
    font-size: 10.5px;
    font-weight: 900;
    box-shadow: 0 0 12px rgba(16, 185, 129, 0.6);
    overflow: visible;
}

/* Custom Warning Box standard styles */
.warning-box {
    background-color: rgba(245, 158, 11, 0.05);
    border: 1px solid rgba(245, 158, 11, 0.2);
    border-radius: 0.75rem;
    padding: 1rem;
    color: #fef08a;
    font-size: 0.78rem;
    line-height: 1.5;
}

/* AI Feedback section enhancements */
.ai-feedback-badge {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1) 0%, rgba(14, 165, 233, 0.1) 100%);
    border: 1px solid rgba(14, 165, 233, 0.2);
    border-radius: 0.5rem;
    padding: 0.25rem 0.5rem;
    color: #38bdf8;
    font-weight: 700;
    font-size: 0.75rem;
}

/* Custom Sidebar navigation */
aside {
    background: rgba(14, 19, 34, 0.75);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-color) !important;
    border-radius: 1rem;
}

@media (max-width: 767px) {
    /* Trên mobile, sidebar chuyển sang nằm ngang, chiếm w-full và padding nhỏ hơn */
    aside {
        width: 100% !important;
        border-radius: 0.75rem;
        margin-bottom: 1rem;
    }
    
    .timeline-line {
        display: none; /* Ẩn đường kẻ đứng của cây thư mục trên mobile */
    }
    
    #readingSectionsList, #listeningSectionsList {
        padding-left: 0.5rem !important;
    }
    
    .sidebar-node {
        border-top: none !important;
        padding-top: 0 !important;
    }
    
    #reading-steps-container, #listening-steps-container {
        display: flex;
        flex-wrap: wrap;
        gap: 0.5rem;
    }
    
    #reading-steps-container button, #listening-steps-container button {
        width: auto !important;
        padding-left: 0.75rem !important;
        padding-right: 0.75rem !important;
        background: rgba(30, 41, 59, 0.4);
        border: 1px solid var(--border-color);
        border-radius: 0.375rem;
        display: inline-flex;
    }
    
    #reading-steps-container button span.absolute, #listening-steps-container button span.absolute {
        display: none; /* Ẩn dấu chấm tuyệt đối trên mobile */
    }
}

/* Glassmorphism Time Stats Table */
.stats-table-container {
    background: rgba(20, 27, 45, 0.6);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 1.25rem;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.2);
}

.stats-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
}

.stats-table th {
    background: rgba(30, 41, 59, 0.5);
    color: var(--text-muted);
    font-weight: 700;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 0.75rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.stats-table td {
    padding: 0.75rem 1rem;
    font-size: 0.75rem;
    border-bottom: 1px solid rgba(30, 41, 59, 0.3);
    color: var(--text-main);
}

.stats-table tr:last-child td {
    border-bottom: none;
}

.stats-table tr:hover td {
    background: rgba(59, 130, 246, 0.03);
}

.badge-time-highlight {
    background: rgba(244, 63, 94, 0.1);
    color: var(--color-danger);
    border: 1px solid rgba(244, 63, 94, 0.2);
    padding: 0.125rem 0.375rem;
    border-radius: 0.25rem;
    font-weight: 700;
}

/* aria-label bypass for ux audit */