* {
    box-sizing: border-box;
}

body {
    font-family:
        system-ui,
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        Roboto,
        Oxygen,
        Ubuntu,
        Cantarell,
        "Open Sans",
        "Helvetica Neue",
        sans-serif;
    font-size: 14px;
    color: #1a1a1a;
    background-color: #EEF6E4;
}

h1,
h2,
h3,
b {
    font-weight: bold;
}

h1 {
    font-size: 3rem;
    text-align: center;
    padding-top: 30px;
    color: #2E7D32;
}

h2 {
    font-size: 1.5rem;
}

p {
    margin-bottom: 1rem;
}

blockquote{
    margin: 20px 0;
    padding: 10px 20px;
    border-left: 4px solid #0ea89c;
    font-style: italic;
    color: #333;
}
i,
em {
    font-style: italic;
}

u {
    text-decoration: underline;
}

a {
    color: #2E7D32;
    text-decoration: none;
}

hr {
    height: 2px;
    background-color: gray;
    border: 1px solid;
}

ul,
ol {
    padding-left: 24px;
    margin-bottom: 16px;
}

li {
    color: #1a1a1a;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

button {
    font-family: inherit;
    font-size: 16px;
    padding: 8px 14px;
    border: 1px solid #a5c78a;
    background-color: #f1f8ec;
    cursor: pointer;
}

input {
    font-family: inherit;
    font-size: 16px;
    padding: 6px 10px;
    border: 1px solid #a5c78a;
}

input:focus {
    outline: none;
    border-color: #2E7D32;
}

ul.mainmenu {
    list-style-type: none; 
    padding-left: 0;
    height: calc(100vh - 60px);
    display: flex;
    justify-content: center;
    align-items: center;
}

ul.mainmenu li a {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-around;
    width: 200px;
    height: 400px;
    margin: 10px;
    font-weight: 500;
    font-size: 1.5rem;
    text-decoration: none;
    color: #ffffff; 
    border-radius: 20px;
    background: #2E7D32;
    box-shadow: 20px 20px 30px -5px rgba(0, 0, 0, 0.5);
    -webkit-box-shadow: 20px 20px 30px -5px rgba(0, 0, 0, 0.5);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

ul.mainmenu li a:hover {
    transform: translateY(-4px);
    box-shadow: 24px 24px 36px -5px rgba(0, 0, 0, 0.55);
}

a button {
    font-size: 1rem;
    font-weight: 500;
    color: #2E7D32;
    background-color: #f1f8ec;
    padding: 10px 20px;
    border-radius: 30px;
    border: none;
    cursor: pointer;
    transition: color 0.2s, background-image 0.2s;
}

a:hover button {
    color: #fff;
    background-image: linear-gradient(90deg, #1B5E20 0%, #a8d94a 100%);
}

a:hover {
    text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.3);
}

/* Bai 1: Nâng cấp menu */
.menu_header {
    text-align: center;
    background-color: #f7fdf2;
    min-height: 100vh;
}

.menu_header .menu {
    background-color: #1B5E20;
    display: flex; 
    justify-content: center;
}

.menu li {
    display: flex;
    align-items: center;
}

.menu li + li {
    border-left: 1px solid rgba(255, 255, 255, 0.2);
}

.menu li a {
    color: #fff;
    text-decoration: none;
    display: inline-block;
    padding: 20px 30px;
    font-size: 1rem;
    text-align: center;
    transition: background-color 0.2s, color 0.2s;
}

.menu li a:hover {
    color: #1B5E20;
    background-color: #d4edda;
}

.menu .active a {
    color: #1B5E20;
    background-color: #d4edda;
}

.menu li a::before {
    content: "\2022";
    display: inline-block;
    margin-right: 10px;
    color: #a8d94a;
}

/* Bai 2: Form */
.form {
    max-width: 600px;
    min-height: 200px;
    background-color: white;
    margin: 50px auto;
    border-radius: 20px;
    padding: 30px;
}
.form {
    border: 1px solid #ccc;
    transition: 0.3s;
}

.form:focus-within {
    border-color: #0ea89c;
    box-shadow: 10px 0 20px rgba(0,0,0,0.3);
}

.form-group:focus {
    outline: none;
    border-color: #0ea89c;
}
.heading {
    margin-bottom: 10px;
    text-align: center;
}
input {
    border-radius: 10px;
}
input:focus{
    outline: none;
    border-color: #0066cc;
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.3);
    -webkit-box-shadow: 0 5px 10px rgba(0, 0, 0, 0.3);
}
input:invalid:not(:placeholder-shown) {
    border-color: red;
}
input[type="date"] {
    border: 1px solid #ccc;
    transition: 0.3s;
}

input[type="date"]:focus {
    border-color: #0ea89c;
}

input[type="date"]:invalid {
    border-color: #ccc; /* giữ bình thường */
}

input[type="date"]:valid {
    border-color: green;
}
input[type="date"]:invalid:focus {
    border-color: red;
}
.avatar-img {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    cursor: pointer;
    margin: 5px;
}
.form-group {
    margin-bottom: 15px;
}
.form-group :is(p, span) {
    font-weight: 500;
}
.form-label {
    display: block;
    cursor: pointer;
}
.form-input {
    width: 100%;
}

.btn {
    border-radius: 10px;
    background-color: #0ea89c;
    color: white;
    width: 100%;
    text-align: center;
}

.btn:hover {
    color: black;
    background-color: #eaeaea;
}
span.required::after {
    content: "*";
    color: red;
    display: inline-block;
    margin-left: 5px;
}
/* Bai 3: Bang gia */
.pricing-wrap {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
    padding: 2rem 1rem;
    max-width: 860px;
    margin: 0 auto;
}
.pricing-card {
    background: #fff;
    border: 0.5px solid #c8e6c9;
    border-radius: 20px;
    padding: 2rem 1.5rem;
    display: flex;
    flex-direction: column;
    position: relative;
    transition: transform 0.22s ease, box-shadow 0.22s ease;
}
.pricing-card:hover {
    box-shadow: 0 16px 40px rgba(46, 125, 50, 0.15), 0 4px 12px rgba(0,0,0,0.08);
}
.pricing-card:nth-child(2) {
    border: 2px solid #ffd700;
    background: #f7fdf2;
}
.pricing-card:nth-child(2):hover {
    box-shadow: 0 20px 48px rgba(46, 125, 50, 0.25), 0 6px 16px rgba(0,0,0,0.10);
}
.plan-name {
    font-size: 1rem;
    font-weight: 500;
    color: #555;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    margin-bottom: 10px;
}
.pricing-card:nth-child(2) .plan-name { color: #2E7D32; }
.price-row {
    display: flex;
    align-items: baseline;
    gap: 4px;
    margin-bottom: 6px;
}
.price-amount {
    font-size: 1.5rem;
    font-weight: bold;
    color: #1a1a1a;
    line-height: 1;
}
.price-currency {
    font-size: 1rem;
    color: #888;
    align-self: flex-start;
    padding-top: 6px;
}
.price-period {
    font-size: 1rem;
    color: #888;
    margin-bottom: 20px;
}
.feature-list {
    list-style: none;
    padding: 0;
    margin: 0 0 auto;
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.feature-list li {
    font-size: 14px;
    padding-left: 22px;
    position: relative;
    line-height: 1.5;
    color: #1a1a1a;
}
.feature-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #2E7D32;
    font-weight: bold;
}
.cta-btn {
    display: block;
    width: 100%;
    margin-top: 24px;
    padding: 11px 0;
    text-align: center;
    font-size: 14px;
    font-weight: 500;
    border-radius: 8px;
    border: 1.5px solid #2E7D32;
    color: #2E7D32;
    background: transparent;
    cursor: pointer;
    transition: background 0.18s, color 0.18s;
    font-family: inherit;
}
.cta-btn:hover {
    background: #2E7D32;
    color: #fff;
}
.cta-btn.filled {
    background: #2E7D32;
    color: #fff;
}

.cta-btn.filled:hover {
    background: #1B5E20;
    border-color: #1B5E20;
}

/* Bai 4: Blog Post */
::selection {
    background-color: #2E7D32;
    color: #ffffff;
}

.blog-container {
    max-width: 780px;
    margin: 0 auto;
    padding: 2rem 1.5rem 4rem;
}
.blog-header h1 {
    font-size: 2.4rem;
    font-weight: bold;
    color: #2E7D32;
    line-height: 1.3;
    margin-bottom: 1.2rem;
    padding-top: 1.5rem;
}
.blog-header img {
    width: 100%;
    height: 360px;
    object-fit: cover;
    border-radius: 16px;
    display: block;
    margin-bottom: 2rem;
}
h2:not(h1),
h3:not(h1),
h4:not(h1) {
    font-size: 1.15rem;
    font-weight: bold;
    color: #1B5E20;
    border-left: 4px solid #a8d94a;
    padding-left: 12px;
    margin: 2.2rem 0 1rem;
    border-radius: 0;
}
.blog-main p {
    margin-bottom: 1.4rem;
    color: #2c2c2c;
    font-size: 15px;
}
.blog-main p:first-of-type::first-letter {
    float: left;
    font-size: 4.5rem;
    font-weight: bold;
    line-height: 0.82;
    color: #2E7D32;
    margin: 6px 10px 0 0;
    font-family: Georgia, serif;
}
.blog-main p::first-line {
    color: #1B5E20;
    font-weight: 600;
    letter-spacing: 0.02em;
}
.blog-main p:nth-of-type(odd) {
    padding-left: 0;
}
.blog-main p:nth-of-type(even) {
    background-color: #f0f9f0;
    border-left: 3px solid #c8e6c9;
    padding: 10px 14px;
    border-radius: 0 8px 8px 0;
}
blockquote::before {
    content: "\201C";
    position: absolute;
    top: -6px;
    left: 10px;
    font-size: 5.5rem;
    color: #a8d94a;
    font-family: Georgia, serif;
    line-height: 1;
    opacity: 0.85;
}
.blog-cmt {
    margin-top: 3.5rem;
    border-top: 2px solid #c8e6c9;
    padding-top: 2rem;
}
.blog-cmt > p {
    font-size: 1.2rem;
    font-weight: bold;
    color: #1B5E20;
    margin-bottom: 1.4rem;
    border-left: 4px solid #a8d94a;
    padding-left: 12px;
}
.cmt {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 1rem 1.2rem;
    margin-bottom: 12px;
    background-color: #ffffff;
    border: 0.5px solid #c8e6c9;
    border-radius: 12px;
    transition: transform 0.22s ease,
                box-shadow 0.22s ease,
                border-color 0.22s ease;
}
.cmt:hover {
    box-shadow: -4px 0 0 #2E7D32, 6px 10px 28px rgba(46, 125, 50, 0.12);
    border-color: #a8d94a;
}
.cmt img {
    width: 52px;
    height: 52px;
    border-radius: 50%;
    object-fit: cover;
    flex-shrink: 0;
    border: 2px solid #c8e6c9;
    transition: border-color 0.22s;
}
.cmt p:nth-of-type(1) {
    font-weight: 600;
    font-size: 14px;
    color: #1B5E20;
    margin: 0;
}
.cmt p:nth-of-type(2) {
    font-size: 14px;
    color: #444;
    margin: 2px 0 0;
}
.cmt:nth-of-type(even) {
    background-color: #f7fdf2;
}
.cmt:nth-of-type(3n) img {
    border-color: #2E7D32;
    box-shadow: 0 0 0 3px #a8d94a;
}