/* Dev A: Dark Mode Variables (สีพื้นฐานสำหรับธีม) */
[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #ffffff;
    --card-bg: #2d2d2d;
    --section-bg: #262626;
    --nav-bg: #1a1a1a;
    --nav-link-color: #ffffff;
    --link-hover-color: #3498db;
    --button-text-color: #ffffff;
    --button-hover-bg: #2980b9;
    --input-bg: #3c3c3c;
    --input-border: #555;
    --input-text-color: #ffffff;
}

[data-theme="light"] {
    --bg-color: #ffffff;
    --text-color: #333333;
    --card-bg: #ffffff;
    --section-bg: #f8f9fa;
    --nav-bg: #f4f4f4;
    --nav-link-color: #333333;
    --link-hover-color: #3498db;
    --button-text-color: #ffffff;
    --button-hover-bg: #2980b9;
    --input-bg: #ffffff;
    --input-border: #ccc;
    --input-text-color: #333333;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color); /* Dev A */
    color: var(--text-color); /* Dev A */
    transition: background-color 0.3s ease, color 0.3s ease; /* Dev A */
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
    font-size: 2.5rem;
    color: var(--text-color);
}

/* Dev A: Header & Navigation Styles */
header {
    background-color: var(--nav-bg);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: background-color 0.3s ease; /* Dev A */
}

.main-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.logo {
    font-size: 1.8rem;
    font-weight: bold;
    color: var(--text-color);
}

.nav-links {
    list-style: none;
    display: flex;
    margin: 0;
    padding: 0;
}

.nav-links li a {
    color: var(--nav-link-color);
    text-decoration: none;
    padding: 0.5rem 1rem;
    transition: color 0.3s ease;
}

.nav-links li a:hover,
.nav-links li a.active { /* Dev A: สำหรับ active state */
    color: var(--link-hover-color);
}

/* Dev A: Theme Toggle Button Styles */
.theme-toggle {
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--nav-link-color);
    margin-left: 20px;
    transition: color 0.3s ease, transform 0.3s ease; /* Dev A */
}

.theme-toggle:hover {
    color: var(--link-hover-color);
}

/* Dev B: Hero Section Styles */
.hero {
    padding: 100px 20px;
    text-align: center;
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.hero-subtitle {
    font-size: 1.8rem;
    color: var(--text-color);
}

.highlight {
    color: #3498db;
}

/* Dev B: Typing Animation Cursor */
.cursor {
    animation: blink 1s infinite;
}

@keyframes blink {
    0%, 50% { opacity: 1; }
    51%, 100% { opacity: 0; }
}

/* Dev B: About Section Styles (รวมส่วน Team Members) */
.about {
    padding: 80px 20px;
    background: var(--section-bg); /* Dev A */
    transition: background-color 0.3s ease; /* Dev A */
}

.team-members {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-bottom: 3rem;
    flex-wrap: wrap; /* ให้ขึ้นบรรทัดใหม่เมื่อหน้าจอเล็ก */
}

.member-card {
    text-align: center;
    background: var(--card-bg); /* Dev A */
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: background-color 0.3s ease, box-shadow 0.3s ease; /* Dev A */
    width: 280px; /* กำหนดความกว้างเพื่อให้อยู่ข้างกัน */
}

.member-card img {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 1rem;
    border: 3px solid #3498db;
}

.member-card h3 {
    font-size: 1.7rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

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


/* Dev B: Skills Section Styles */
.skills {
    padding: 80px 20px;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    text-align: center;
}

.skill-item {
    background: var(--card-bg); /* Dev A */
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    font-weight: bold;
    color: var(--text-color);
    transition: background-color 0.3s ease, box-shadow 0.3s ease; /* Dev A */
}

/* Dev B: Projects Section Styles */
.projects {
    padding: 80px 20px;
    background: var(--section-bg); /* Dev A */
    transition: background-color 0.3s ease; /* Dev A */
}

/* Dev B: Project Filter Buttons */
.filter-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 10px 20px;
    border: none;
    background: transparent;
    color: #666;
    cursor: pointer;
    border-radius: 25px;
    transition: all 0.3s ease;
    font-weight: 500;
    position: relative;
    overflow: hidden;
}

.filter-btn.active,
.filter-btn:hover {
    background: #3498db;
    color: white;
}

/* Dev B: Ripple Effect */
.filter-btn .ripple {
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.7);
    transform: scale(0);
    animation: ripple-animation 0.6s linear;
    pointer-events: none;
}

@keyframes ripple-animation {
    to {
        transform: scale(4);
        opacity: 0;
    }
}

/* Dev B: Project Card */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.project-card {
    background: var(--card-bg); /* Dev A */
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: background-color 0.3s ease, box-shadow 0.3s ease, opacity 0.3s ease, height 0.3s ease, padding 0.3s ease, margin 0.3s ease; /* Dev A & B */
    display: flex; /* เพื่อจัดเรียงเนื้อหาภายใน card */
    flex-direction: column;
}

.project-card h3 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.project-card p {
    margin-bottom: 1rem;
    flex-grow: 1; /* ทำให้ p กินพื้นที่ที่เหลือ */
    color: var(--text-color);
}

.project-card a {
    display: inline-block;
    background-color: #3498db;
    color: white;
    padding: 10px 20px;
    border-radius: 5px;
    text-decoration: none;
    transition: background-color 0.3s ease;
    align-self: flex-start; /* จัดให้ปุ่มอยู่ด้านล่างซ้าย */
}

.project-card a:hover {
    background-color: #2980b9;
}

/* Dev B: Hide/Show Project Cards */
.project-card.hide {
    opacity: 0;
    height: 0;
    padding: 0;
    margin: 0;
    overflow: hidden;
    pointer-events: none; /* ป้องกันการคลิกเมื่อซ่อน */
}


/* Dev B: Contact Section Styles */
.contact {
    padding: 80px 20px;
}

.contact-form {
    max-width: 600px;
    margin: 0 auto;
    background: var(--card-bg); /* Dev A */
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
    gap: 15px;
    transition: background-color 0.3s ease, box-shadow 0.3s ease; /* Dev A */
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--input-border);
    border-radius: 5px;
    background-color: var(--input-bg); /* Dev A */
    color: var(--input-text-color); /* Dev A */
    transition: border-color 0.3s ease, background-color 0.3s ease, color 0.3s ease; /* Dev A */
}

.contact-form input:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: #3498db;
}

.contact-form .btn-submit {
    background-color: #3498db;
    color: var(--button-text-color);
    border: none;
    padding: 15px 25px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: bold;
    transition: background-color 0.3s ease;
}

.contact-form .btn-submit:hover {
    background-color: var(--button-hover-bg);
}

/* Dev B: Footer Styles */
footer {
    text-align: center;
    padding: 30px 20px;
    background-color: var(--nav-bg); /* ใช้สีเดียวกับ nav bar */
    color: var(--nav-link-color);
    margin-top: 50px;
    transition: background-color 0.3s ease, color 0.3s ease; /* Dev A */
}


/* Dev A: Loading Animation Styles */
.loader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-color); /* ใช้สีพื้นหลังตามธีม */
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.5s ease;
    overflow: hidden;
}

.loader-content {
    text-align: center;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 5px solid #f3f3f3;
    border-top: 5px solid #3498db;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.progress-bar-container {
    width: 200px;
    height: 10px;
    background-color: #f3f3f3;
    border-radius: 5px;
    margin: 1rem auto;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    width: 0%;
    background-color: #3498db;
    border-radius: 5px;
    transition: width 0.15s ease-out;
}

.loader.fade-out {
    opacity: 0;
    pointer-events: none;
}

/* Dev A: Scroll Progress Indicator Styles */
.scroll-progress {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: rgba(255, 255, 255, 0.2);
    z-index: 1001;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #3498db, #f39c12);
    width: 0%;
    transition: width 0.1s ease;
}




/* Dev B: Back to Top Button Styles */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease, transform 0.1s ease; /* Dev B: เพิ่ม transform */
    z-index: 1000;
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: #2980b9;
    transform: translateY(-2px);
}

/* Responsive Design (สำหรับทั้ง Dev A และ Dev B) */
@media (max-width: 768px) {
    .main-nav {
        flex-direction: column;
        align-items: flex-start;
    }

    .nav-links {
        flex-direction: column;
        width: 100%;
        margin-top: 1rem;
    }

    .nav-links li {
        width: 100%;
        text-align: center;
        margin-bottom: 0.5rem;
    }

    .theme-toggle {
        align-self: flex-end; /* จัดให้ปุ่มอยู่ขวาบนสุด */
        margin-top: -30px; /* เลื่อนขึ้นให้ชิดขวาบน */
        margin-right: 20px;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.4rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .team-members {
        flex-direction: column;
        align-items: center;
    }

    .member-card {
        width: 100%;
        max-width: 300px;
    }

    .projects-grid {
        grid-template-columns: 1fr;
    }
}

 /* Skills grid on small screens */
    .skills-grid {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); /* ลดขนาด minmax ลง */
        gap: 15px; /* ลดระยะห่าง */
    }

    .skill-item i {
        font-size: 2.5rem; /* ลดขนาดไอคอนลงสำหรับมือถือ */
    }

    .skill-item span {
        font-size: 0.9rem; /* ลดขนาดตัวอักษรลงสำหรับมือถือ */
    }

    /* responsive Project Card Image Styles */
.project-card .project-image-container {
    width: 100%; 
    height: 200px; 
    overflow: hidden; 
    border-radius: 8px; 
    margin-bottom: 1rem; 
    display: flex; 
    justify-content: center; 
    align-items: center; 
    background-color: #f0f0f0; 
}

.project-card .project-image-container img {
    width: 100%; 
    height: 100%; 
    object-fit: cover; 
    display: block; 
    transition: transform 0.3s ease; 
}

.project-card:hover .project-image-container img {
    transform: scale(1.05); 
}


.project-card p {
    margin-bottom: 1.5rem; 
}


.project-card:hover {
    transform: translateY(-5px); 
    box-shadow: 0 8px 20px rgba(0,0,0,0.15); 
}