/* ================================
   GLOBAL LAYEOUT
================================ */
* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding-top: 52px;
    /* For fixed header */
    font-family: Arial, Helvetica, sans-serif;
    background: #3a3a3a;
    color: #ffffff;
    min-height: 100vh;
}

/* ================================
   TOP TAB NAV (FIXED)
================================ */
.top-tabs {
    display: flex;
    height: 52px;
    background: linear-gradient(#3a3a3a, #2b2b2b);
    border-bottom: 1px solid #1a1a1a;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
}

/* TAB ITEM */
.tab {
    flex: 1;
    text-align: center;
    line-height: 52px;
    cursor: pointer;
    position: relative;
    user-select: none;
    color: #aaa;
    font-size: 14px;
    transition: color 0.2s;
}

.tab.active {
    color: #ffffff;
}

/* Non-active overlay (Glass effect) */
.tab::before {
    content: "";
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, .25);
    transition: background 0.2s;
}

.tab.active::before {
    background: transparent;
}

/* Active indicator line */
.tab::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: 0;
    width: 100%;
    height: 4px;
    background: #555;
    transition: all 0.25s ease;
}

.tab.active::after {
    background: linear-gradient(#4fd2ff, #1dafff, #118fc7);
}

.tab:hover {
    color: #fff;
}

.tab:hover::before {
    background: rgba(0, 0, 0, .1);
}

/* ================================
   SPA CONTAINER
================================ */
#app {
    min-height: calc(100vh - 52px);
    padding: 0;
    max-width: 480px;
    margin: 0 auto;
}

/* ================================
   RESPONSIVE
================================ */
@media (max-width: 480px) {
    .tab {
        font-size: 13px;
    }
}