/* Biến CSS (Tông màu Xanh/Trắng chủ đạo) */
:root {
    --primary-color: #007BFF; /* Xanh dương đậm */
    --secondary-color: #0056b3; /* Xanh đậm hơn cho hover/active */
    --accent-color: #28a745; /* Màu nhấn (CTA) */
    --text-dark: #333;
    --text-light: #f4f4f4;
    --background-light: #f8f9fa; /* Xám nhạt */
}

/* Thiết lập cơ bản */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

.bg-light {
    background-color: var(--background-light);
}

.section {
    padding: 80px 0;
    text-align: center;
}

.section h3 {
    font-size: 2.5em;
    margin-bottom: 15px;
    color: var(--primary-color);
}

/* Header (Sticky) */
.header {
    background-color: #fff;
    border-bottom: 1px solid #eee;
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo a {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 1.8em;
    font-weight: bold;
}

.navbar a:not(.cta-button) {
    color: var(--text-dark);
    text-decoration: none;
    margin-left: 25px;
    font-weight: 500;
    transition: color 0.3s;
}

.navbar a:hover:not(.cta-button) {
    color: var(--secondary-color);
}

/* CTA Buttons */
.cta-button, .primary-cta {
    background-color: var(--accent-color);
    color: white;
    padding: 10px 20px;
    border-radius: 5px;
    text-decoration: none;
    margin-left: 20px;
    font-weight: bold;
    transition: background-color 0.3s;
    border: none;
    cursor: pointer;
}

.cta-button:hover, .primary-cta:hover {
    background-color: #1e7e34;
}
.alt-cta {
    background-color: var(--accent-color);
}

/* ================================== */
/* CSS cho Hero Slider */
/* ================================== */

.hero-section {
    position: relative;
    overflow: hidden; 
    padding: 0; /* Loại bỏ padding cũ */
    height: 450px; /* Thiết lập chiều cao cố định cho slider */
}

.slider-container {
    position: relative;
    height: 100%;
    width: 100%;
}

.slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0; 
    transition: opacity 1.5s ease-in-out; 
    
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
    color: var(--text-light);
    
    background: var(--primary-color);
}

/* Thay đổi màu nền cho các slide khác nhau */
.slide:nth-child(2) {
    background-color: #0d6efd; 
}

.slide:nth-child(3) {
    background-color: var(--secondary-color);
}

.active-slide {
    opacity: 1; 
    z-index: 5;
}

.slide .container {
    z-index: 10; 
}
.slide h2 {
    font-size: 3.5em;
    margin-bottom: 20px;
}
.slide p {
    font-size: 1.5em;
    margin-bottom: 40px;
    font-weight: 300;
}

/* Nút điều hướng (Dấu chấm) */
.slider-controls {
    text-align: center;
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 15;
}

.dot {
    height: 12px;
    width: 12px;
    margin: 0 4px;
    background-color: rgba(255, 255, 255, 0.4); 
    border-radius: 50%;
    display: inline-block;
    transition: background-color 0.6s ease;
    cursor: pointer;
    border: 1px solid white; 
}

.active-dot {
    background-color: white; 
}


/* About Section */
.about-content {
    max-width: 800px;
    margin: 0 auto;
}
.stats-grid {
    display: flex;
    justify-content: space-around;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid #eee;
}
.stat span {
    display: block;
    font-size: 2.5em;
    font-weight: bold;
    color: var(--accent-color);
}
.stat p {
    font-size: 1em;
    color: #6c757d;
}

/* Services Section (Cards tương tác) */
.service-cards {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 30px;
    margin-top: 40px;
}

.card {
    flex-basis: calc(25% - 30px); 
    min-width: 250px;
    background: #fff;
    padding: 30px;
    border-radius: 10px;
    border: 1px solid #e0e0e0;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    transition: all 0.4s ease-in-out; 
    text-align: left;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
    background-color: var(--primary-color); 
    color: var(--text-light); 
    border-color: var(--primary-color);
}

.card .icon {
    font-size: 3em;
    color: var(--primary-color);
    margin-bottom: 15px;
    transition: all 0.4s;
}

.card:hover .icon {
    color: var(--accent-color); 
    transform: scale(1.1);
}

.card h4 {
    font-size: 1.5em;
    margin-bottom: 10px;
}

.card p {
    color: #6c757d;
    transition: color 0.4s;
}

.card:hover p {
    color: var(--text-light); 
}

/* Dự Án Tiêu Biểu (Grid) */
.projects-section .subtitle {
    font-size: 1.2em;
    color: #6c757d;
    margin-top: -15px;
    margin-bottom: 50px;
}

.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.project-card {
    background: #fff;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s, box-shadow 0.3s;
    text-align: left;
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

.project-image {
    height: 200px;
    background-size: cover;
    background-position: center;
    background-color: #e9ecef; 
}

.project-info {
    padding: 20px;
}

.project-info h4 {
    font-size: 1.4em;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.project-tag {
    display: inline-block;
    background-color: #e9ecef;
    color: var(--primary-color);
    padding: 5px 10px;
    border-radius: 20px;
    font-size: 0.8em;
    font-weight: bold;
    margin-bottom: 10px;
}

.project-link {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: bold;
    margin-top: 10px;
    display: inline-block;
}

.project-link i {
    margin-left: 5px;
    transition: transform 0.3s;
}

.project-link:hover i {
    transform: translateX(5px);
}

.project-cta-all {
    margin-top: 50px;
}

/* Quy Trình Làm Việc (Timeline) */
.process-steps {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-top: 50px;
    position: relative;
    padding: 20px 0;
}

/* Đường kẻ Timeline */
.process-steps::before {
    content: '';
    position: absolute;
    top: 60px; 
    left: 10%;
    right: 10%;
    height: 3px;
    background-color: #ddd;
    z-index: 1;
}

.step {
    flex-basis: 18%; 
    text-align: center;
    position: relative;
    z-index: 2; 
    background: var(--background-light); 
}

.step-icon-wrap {
    position: relative;
    display: inline-block;
    margin-bottom: 20px;
}

/* Vòng tròn số bước */
.step-number {
    width: 60px;
    height: 60px;
    background-color: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.8em;
    font-weight: bold;
    margin: 0 auto;
    border: 5px solid white; 
    box-shadow: 0 0 0 3px var(--primary-color);
    transition: transform 0.3s;
}

/* Icon bên trong */
.step-icon {
    position: absolute;
    top: -10px; 
    right: -10px; 
    font-size: 1.2em;
    color: var(--accent-color); 
    background-color: white;
    padding: 5px;
    border-radius: 50%;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.step h4 {
    color: var(--primary-color);
    font-size: 1.3em;
    margin-bottom: 10px;
}

/* Hiệu ứng hover nhẹ */
.step:hover .step-number {
    transform: scale(1.05);
    background-color: var(--secondary-color);
}

/* Footer */
.footer {
    background-color: var(--text-dark);
    color: var(--text-light);
    padding: 30px 0;
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.social-icons a {
    color: var(--text-light);
    font-size: 1.2em;
    margin-left: 15px;
    transition: color 0.3s;
}

.social-icons a:hover {
    color: var(--primary-color);
}


/* ================================== */
/* Responsive Design (Mobile First) */
/* ================================== */
@media (max-width: 992px) {
    /* Điều chỉnh chung */
    .section { padding: 60px 0; }
    
    /* Hero Section */
    .hero-section { height: 350px; }
    .slide h2 { font-size: 2.2em; }
    .slide p { font-size: 1.1em; }

    /* Header */
    .header .container { flex-direction: column; }
    .navbar { margin-top: 10px; display: flex; flex-direction: column; }
    .navbar a { margin: 5px 0; }
    .cta-button { margin-left: 0; margin-top: 10px; }

    /* Services & Projects */
    .card { flex-basis: calc(50% - 15px); } 
    .project-grid { grid-template-columns: 1fr; } 

    /* Process Steps (Chuyển sang Timeline Dọc) */
    .process-steps {
        flex-wrap: wrap;
        gap: 40px;
        flex-direction: column; 
        align-items: center;
    }

    .process-steps::before {
        top: 0;
        bottom: 0;
        left: 50%; 
        transform: translateX(-50%);
        width: 3px;
        height: 100%;
        background-color: #ddd;
    }

    .step {
        flex-basis: 100%;
        text-align: center;
        padding: 20px 0;
    }
    
    .step-icon-wrap {
        margin: 0 auto;
    }

    /* Footer */
    .footer .container {
        flex-direction: column;
    }
    .social-icons {
        margin-top: 15px;
    }
}