:root {
    --primary: #4a90e2;
    --secondary: #50e3c2;
    --bg: #f4f7f6;
    --text: #333;
    --card: #ffffff;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    height: 100vh;
}

header {
    background-color: var(--primary);
    color: white;
    padding: 15px;
    text-align: center;
    font-size: 1.2rem;
    font-weight: bold;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

nav {
    position: fixed;
    bottom: 0;
    width: 100%;
    background: var(--card);
    display: flex;
    justify-content: space-around;
    padding: 10px 0;
    box-shadow: 0 -2px 10px rgba(0,0,0,0.05);
    border-top: 1px solid #ddd;
    z-index: 100;
}

nav button {
    background: none;
    border: none;
    font-size: 24px;
    color: #888;
    cursor: pointer;
    flex-grow: 1;
}

nav button.active {
    color: var(--primary);
}

main {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    margin-bottom: 60px;
}

.screen {
    display: none;
    animation: fadeIn 0.3s;
}

.screen.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.card {
    background: var(--card);
    padding: 15px;
    border-radius: 10px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
    margin-bottom: 15px;
}

input, select, button.action-btn {
    width: 100%;
    padding: 12px;
    margin: 8px 0;
    border: 1px solid #ddd;
    border-radius: 8px;
    box-sizing: border-box;
    font-size: 16px;
}

button.action-btn {
    background-color: var(--primary);
    color: white;
    border: none;
    font-weight: bold;
    cursor: pointer;
}

button.delete-btn {
    background-color: #e74c3c;
    color: white;
    border: none;
    padding: 5px 10px;
    border-radius: 5px;
    margin-left: 10px;
}

.import-area {
    border: 2px dashed #ccc;
    padding: 10px;
    text-align: center;
    margin-top: 10px;
    border-radius: 8px;
    background: #fafafa;
}

.import-area label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
    color: #666;
    cursor: pointer;
}

ul { list-style: none; padding: 0; }
li {
    background: #fff;
    border-bottom: 1px solid #eee;
    padding: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.result-box {
    font-size: 2rem;
    text-align: center;
    color: var(--primary);
    margin: 20px 0;
    font-weight: bold;
    min-height: 50px;
}