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

body {
    font-family: 'Segoe UI', sans-serif;
    background: #f7f7f7;
    color: #222;
}

/* HEADER */
header {
    padding: 40px 20px;
    text-align: center;
    background: white;
    border-bottom: 2px solid #eee;
}

header h1 {
    font-size: 26px;
    font-weight: 600;
}

header p {
    margin-top: 6px;
    font-size: 14px;
    color: #666;
}

/* MAIN LAYOUT */
.container {
    display: flex;
    max-width: 1000px;
    margin: 40px auto;
    gap: 30px;
    padding: 0 20px;
}

/* SIDEBAR */
.sidebar {
    width: 200px;
}

.sidebar h3 {
    margin-bottom: 15px;
    font-size: 15px;
    color: #444;
}

.sidebar button {
    width: 100%;
    padding: 10px;
    margin-bottom: 10px;
    background: #222;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: 0.2s ease;
}

.sidebar button:hover {
    background: #555;
}

/* MAIN CONTENT */
.main-content {
    flex: 1;
    background: white;
    padding: 25px;
    border-radius: 8px;
    border: 1px solid #eee;
}

/* ACTIVITY BUTTONS */
#activity-buttons button {
    display: block;
    width: 100%;
    padding: 10px;
    margin-bottom: 10px;
    background: #555;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: 0.2s ease;
}

#activity-buttons button:hover {
    background: #222;
}

footer {
    text-align: center;
    padding: 20px;
    font-size: 14px;
    color: #777;
    border-top: 1px solid #eee;
    margin-top: 40px;
    background: white;
}

/* ======================
   DARK MODE STYLES
====================== */
body.dark-mode {
    background-color: #222;
    color: #f7f7f7;
}

body.dark-mode header {
    background-color: #333;
    color: #f7f7f7;
    border-bottom: 2px solid #555;
}

body.dark-mode .sidebar {
    background-color: #333;
}

body.dark-mode .sidebar h3 {
    color: #f7f7f7;
}

body.dark-mode .sidebar button {
    background-color: #555;
    color: #f7f7f7;
}

body.dark-mode .sidebar button:hover {
    background-color: #777;
}

body.dark-mode .main-content {
    background-color: #333;
    color: #f7f7f7;
    border: 1px solid #555;
}

body.dark-mode #activity-buttons button {
    background-color: #666;
    color: #f7f7f7;
}

body.dark-mode #activity-buttons button:hover {
    background-color: #888;
}

body.dark-mode footer {
    background-color: #222;
    color: #ccc;
    border-top: 1px solid #555;
}

/* Smooth transition for dark mode toggle */
body, header, .sidebar, .main-content, footer, #activity-buttons button {
    transition: all 0.3s ease;
}