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

body {
    font-family: Segoe UI, Arial, sans-serif;
    background: #f5f7fb;
    color: #333;
}

header {
    background: #1677ff;
    color: white;
    padding: 16px;
}

header h1 {
    font-size: 24px;
}

nav {
    display: flex;
    gap: 10px;
    padding: 15px;
    background: white;
    border-bottom: 1px solid #ddd;
}

nav button {
    padding: 10px 16px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    background: #1677ff;
    color: white;
}

nav button:hover {
    background: #0958d9;
}

main {
    padding: 20px;
}

.card {
    background: white;
    padding: 20px;
    border-radius: 12px;
    box-shadow:
        0 2px 8px rgba(0,0,0,0.08);
}

input {
    width: 100%;
    padding: 10px;
    margin-top: 10px;
    margin-bottom: 10px;
}

ul {
    margin-top: 15px;
}

li {
    padding: 8px;
    border-bottom: 1px solid #eee;
}

.hidden {
    display: none;
}