html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background-color: #8d8d8d;   /* change this to any color you like */
    transition: background-color 0.3s ease;
}

/* NAVBAR */
.navbar {
    position: fixed;
    width: 100%;
    top: 0;
    background: #0d2158;
    color: white;
    display: flex;
    justify-content: space-between;
    padding: 15px 30px;
    box-sizing: border-box;
    z-index: 1000;
}

.navbar a {
    color: white;
    text-decoration: none;
    margin-left: 20px;
}

/* HERO */
.hero {
    height: 100vh;
    background: linear-gradient(135deg, #0f1935, #8120d1);
    color: white;
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
}

/* CONTENT */
.content-section {
    padding: 120px 20px 60px;
    max-width: 900px;
    margin: auto;
}

.activity {
    background: #f9f5fc;
    padding: 20px;
    margin: 15px 0;
    border-radius: 12px;
}

button {
    padding: 8px 30px;
    background: #83b5ee;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

button:hover {
    background: #0b2a4d;
}

/* DARK MODE */
.dark-mode {
    background-color: #121212 !important;
    color: rgb(0, 0, 0);
}

.dark-mode .activity {
    background-color: #fffcfc;
}

.dark-mode .navbar {
    background-color: #ffeded;
}

/* IMAGE FRAME */
.image-frame {
    width: 200px;
    height: 130px;
    margin: auto;
    overflow: hidden;
    border-radius: 12px;
    border: 3px solid #080c1a;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

.image-frame img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

/* ===== WEEK 3 GRADE CALCULATOR ===== */

.grade-box {
    background: #ffffff;
    padding: 15px;
    margin: 15px 0;
    border-radius: 10px;
    box-shadow: 0 3px 8px rgba(0,0,0,0.1);
}

.grade-box input {
    display: block;
    margin: 5px 0;
    padding: 8px;
    width: 100%;
    max-width: 250px;
}

.grade-box button {
    margin-top: 10px;
}

.grade-final {
    margin-top: 20px;
    text-align: center;
}