:root {
    --primary-color: #6200EE; /* PrimaryPurple giống Android */
    --text-dark: #333;
    --text-grey: #666;
    --bg-color: #F5F5F5;
}

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

body {
    font-family: 'Roboto', sans-serif;
    background-color: var(--bg-color);
    height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Container chính chứa nội dung */
.app-container {
    flex: 1; /* Chiếm hết khoảng trống còn lại */
    overflow-y: auto; /* Cho phép cuộn nội dung */
    padding-bottom: 70px; /* Trừa chỗ cho Bottom Nav */
    position: relative;
}

/* Bottom Navigation Bar */
.bottom-nav {
    position: fixed;
    bottom: 0;
    width: 100%;
    height: 60px;
    background: white;
    display: flex;
    justify-content: space-around;
    align-items: center;
    border-top: 1px solid #ddd;
    box-shadow: 0 -2px 5px rgba(0,0,0,0.05);
    z-index: 1000;
}

.nav-link {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-decoration: none;
    color: var(--text-grey);
    font-size: 12px;
}

.nav-link i {
    font-size: 24px;
    margin-bottom: 4px;
}

/* Active State cho Nav */
.nav-link.nav-active {
    color: var(--primary-color);
}

/* Styles chung cho các màn hình */
.screen-title {
    font-size: 24px;
    font-weight: bold;
    color: var(--text-dark);
    margin: 20px;
}

.card {
    background: white;
    margin: 10px 20px;
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}