:root {
    --primary-color: #003865;       /* Xanh dương đặc trưng ATS */
    --primary-light: #1A5485;       /* Xanh dương sáng hơn chút */
    --primary-hover: #00284D;
    
    --accent-color: #e8f1f8;        /* Xanh dương cực nhạt, rất thanh lịch, tươi sáng */
    --accent-gold: #D4AF37;         /* Vàng đồng sang trọng nếu cần điểm nhấn */
    
    --bg-color: #f4f7fa;            /* Nền trắng xám cực nhẹ, sang trọng */
    --surface-color: #ffffff;
    
    --text-main: #1a202c;           /* Đen chuyên nghiệp */
    --text-muted: #64748b;
    --border-color: #e2e8f0;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
}

.app-container {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 280px;
    background-color: var(--surface-color);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 32px 0;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    box-shadow: 4px 0 15px rgba(0, 56, 101, 0.04);
    z-index: 100;
}

.logo-container {
    padding: 0 24px 32px;
    margin-bottom: 12px;
    text-align: center;
}

.logo {
    max-width: 140px;
    height: auto;
    margin-bottom: 12px;
}

.slogan {
    font-size: 11px;
    color: var(--text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.menu {
    display: flex;
    flex-direction: column;
    padding: 0 16px;
}

.menu-item {
    padding: 14px 18px;
    text-decoration: none;
    color: var(--text-muted);
    font-size: 14.5px;
    font-weight: 500;
    border-radius: 12px;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 14px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

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

.menu-item.active {
    background-color: var(--accent-color);
    color: var(--primary-color);
    font-weight: 600;
}

/* Hiệu ứng thanh dọc bên trái cho menu active */
.menu-item.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    height: 60%;
    width: 4px;
    background-color: var(--primary-color);
    border-radius: 0 4px 4px 0;
}

.menu-item i {
    width: 20px;
    text-align: center;
    font-size: 16px;
    transition: transform 0.3s ease;
}

.menu-item.active i {
    transform: scale(1.15);
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: 280px;
    padding: 48px 60px;
    max-width: 1400px;
}

/* Section Transitions */
.section {
    display: none;
    opacity: 0;
    transform: translateY(15px);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.section.active {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

.header {
    margin-bottom: 40px;
    position: relative;
}

/* Thêm điểm nhấn gradient nhẹ cho tiêu đề chính */
.header h1 {
    font-size: 32px;
    font-weight: 800;
    background: linear-gradient(90deg, var(--primary-color) 0%, var(--primary-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 12px;
    letter-spacing: -0.5px;
}

.header p {
    color: var(--text-muted);
    font-size: 16px;
    max-width: 800px;
    line-height: 1.7;
}

/* Stats Container */
.stats-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-bottom: 40px;
}

/* Glassmorphism / Luxury card effect */
.stat-card {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: 28px 32px;
    border-radius: 20px;
    border: 1px solid rgba(255, 255, 255, 1);
    box-shadow: 0 4px 20px rgba(0, 56, 101, 0.04), inset 0 0 0 1px rgba(255,255,255,0.5);
    transition: all 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 30px rgba(0, 56, 101, 0.08);
}

/* Xử lý căn chỉnh "4.2 Tỷ" */
.stat-card h2 {
    display: flex;
    align-items: baseline;
    gap: 6px;
    margin-bottom: 8px;
    color: var(--primary-color);
}

.stat-card .number {
    font-size: 42px;
    font-weight: 800;
    line-height: 1;
    letter-spacing: -1px;
}

.stat-card .unit {
    font-size: 18px;
    font-weight: 600;
    color: var(--primary-light);
}

.stat-card p {
    color: var(--text-muted);
    font-size: 15px;
    font-weight: 500;
}

/* Form Card */
.card {
    background-color: var(--surface-color);
    border-radius: 20px;
    border: 1px solid var(--border-color);
    padding: 48px;
    box-shadow: 0 10px 40px rgba(0, 56, 101, 0.03);
    position: relative;
    overflow: hidden;
}

/* Subtle accent line on top of card */
.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--primary-light));
}

.card h3 {
    font-size: 24px;
    color: var(--text-main);
    margin-bottom: 12px;
    font-weight: 700;
    letter-spacing: -0.3px;
}

.card .subtitle {
    color: var(--text-muted);
    font-size: 15px;
    margin-bottom: 36px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--border-color);
    line-height: 1.6;
}

/* Form Styles */
.form-group {
    margin-bottom: 24px;
}

.form-row-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 28px;
}

.form-group label {
    display: block;
    font-size: 14.5px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-main);
}

.form-control {
    width: 100%;
    padding: 16px 20px;
    border: 1.5px solid var(--border-color);
    border-radius: 12px;
    font-size: 15px;
    font-family: inherit;
    transition: all 0.25s ease;
    background-color: #f8fafc;
    color: var(--text-main);
}

.form-control:hover {
    border-color: #cbd5e1;
}

.form-control:focus {
    outline: none;
    background-color: #fff;
    border-color: var(--primary-light);
    box-shadow: 0 0 0 4px rgba(0, 56, 101, 0.08);
}

.upload-area {
    border: 2px dashed #cbd5e1;
    border-radius: 12px;
    padding: 48px 24px;
    text-align: center;
    background-color: #f8fafc;
    cursor: pointer;
    transition: all 0.3s ease;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background-color: var(--accent-color);
    transform: translateY(-2px);
}

.upload-area i {
    font-size: 36px;
    color: var(--primary-light);
    margin-bottom: 16px;
    transition: transform 0.3s ease;
}

.upload-area:hover i {
    transform: scale(1.1);
}

.upload-area p {
    color: var(--text-muted);
    font-size: 15px;
    font-weight: 500;
}

small {
    display: block;
    margin-top: 8px;
    color: var(--text-muted);
    font-size: 13.5px;
}

/* Buttons */
.btn {
    padding: 16px 32px;
    border-radius: 12px;
    font-size: 15.5px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 12px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-light) 100%);
    color: white;
    box-shadow: 0 6px 16px rgba(0, 56, 101, 0.2);
}

.btn-primary:hover {
    box-shadow: 0 8px 24px rgba(0, 56, 101, 0.3);
    transform: translateY(-2px);
}

.btn-primary:active {
    transform: translateY(0);
}

.form-actions {
    display: flex;
    align-items: center;
    gap: 24px;
    margin-top: 40px;
    padding-top: 32px;
    border-top: 1px solid var(--border-color);
}

.processing-time {
    font-size: 14.5px;
    color: var(--text-muted);
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 8px;
}

.processing-time i {
    color: #059669; /* Green success */
    font-size: 18px;
}