:root {
    --primary: #2563eb;
    --primary-d: #1d4ed8;
    --primary-l: #dbeafe;
    --bg: #f1f5f9;
    --panel: #ffffff;
    --border: #e2e8f0;
    --text: #0f172a;
    --text-mute: #64748b;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --shadow: 0 1px 3px rgba(15, 23, 42, .08), 0 1px 2px rgba(15, 23, 42, .04);
    --shadow-lg: 0 10px 30px rgba(15, 23, 42, .12);
    --radius: 16px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg); color: var(--text); line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}
button { font-family: inherit; cursor: pointer; }
a { color: var(--primary); text-decoration: none; }
h1, h2, h3 { line-height: 1.2; }

/* ---------- Boot ---------- */
.boot { min-height: 100vh; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 16px; color: var(--text-mute); }
.boot-spinner { width: 34px; height: 34px; border: 3px solid var(--primary-l); border-top-color: var(--primary); border-radius: 50%; animation: spin .8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- Buttons ---------- */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 8px;
    border: 1px solid transparent; border-radius: 11px; font-size: 14px; font-weight: 600;
    padding: 10px 18px; transition: background .15s, border-color .15s, transform .05s, box-shadow .15s;
}
.btn:active { transform: translateY(1px); }
.btn.lg { padding: 13px 24px; font-size: 15px; }
.btn.sm { padding: 7px 12px; font-size: 13px; border-radius: 9px; }
.btn.full { width: 100%; }
.btn.primary { background: var(--primary); color: #fff; box-shadow: 0 2px 10px rgba(37,99,235,.28); }
.btn.primary:hover { background: var(--primary-d); }
.btn.primary:disabled { opacity: .6; cursor: default; }
.btn.ghost { background: var(--panel); color: var(--text); border-color: var(--border); }
.btn.ghost:hover { background: var(--bg); }

/* ---------- Shell ---------- */
.app-shell { min-height: 100vh; display: flex; flex-direction: column; }
.main { flex: 1; }

.topbar {
    height: 62px; background: rgba(255,255,255,.85); backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border); display: flex; align-items: center;
    padding: 0 24px; gap: 20px; position: sticky; top: 0; z-index: 500;
}
.topbar .brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 17px; }
.topbar .brand .logo { width: 30px; height: 30px; border-radius: 8px; background: var(--primary); display: grid; place-items: center; color: #fff; }
.topbar .brand small { font-weight: 500; color: var(--text-mute); font-size: 12px; margin-left: 2px; }
.topbar .spacer { flex: 1; }
.tabs { display: flex; gap: 4px; }
.tabs button {
    background: transparent; border: none; padding: 8px 14px; border-radius: 9px;
    font-size: 14px; font-weight: 600; color: var(--text-mute);
}
.tabs button:hover { background: var(--bg); color: var(--text); }
.tabs button.on { background: var(--primary-l); color: var(--primary-d); }

.balance-chip {
    display: inline-flex; align-items: center; gap: 7px; background: var(--panel);
    border: 1px solid var(--border); border-radius: 999px; padding: 7px 14px;
    font-size: 13px; color: var(--text-mute); box-shadow: var(--shadow);
}
.balance-chip b { color: var(--text); font-weight: 700; }
.balance-chip svg { color: var(--warning); }
.balance-chip.low { border-color: #fecaca; background: #fef2f2; }
.balance-chip.low svg { color: var(--danger); }

.page { max-width: 1080px; margin: 0 auto; padding: 32px 24px 60px; }

/* ---------- Hero ---------- */
.hero { text-align: center; padding: 48px 0 40px; }
.hero-badge {
    display: inline-block; background: var(--primary-l); color: var(--primary-d);
    font-size: 12.5px; font-weight: 700; padding: 6px 14px; border-radius: 999px; margin-bottom: 20px;
    letter-spacing: .2px;
}
.hero h1 { font-size: 40px; font-weight: 800; letter-spacing: -.5px; max-width: 720px; margin: 0 auto; }
.hero-sub { color: var(--text-mute); font-size: 17px; margin: 18px auto 28px; max-width: 620px; }
.hero-sub b { color: var(--text); }
.hero-cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

/* ---------- Principle ---------- */
.principle { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin: 20px 0 56px; }
.principle-card {
    background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 22px; box-shadow: var(--shadow);
}
.principle-card .pc-ico {
    width: 44px; height: 44px; border-radius: 12px; background: var(--primary-l); color: var(--primary-d);
    display: grid; place-items: center; margin-bottom: 14px;
}
.principle-card h3 { font-size: 15.5px; margin-bottom: 6px; }
.principle-card p { font-size: 13.5px; color: var(--text-mute); }

/* ---------- Section heads ---------- */
.sim-head { text-align: center; margin-bottom: 26px; }
.sim-head h2 { font-size: 28px; font-weight: 800; letter-spacing: -.3px; }
.sim-head p { color: var(--text-mute); font-size: 15px; margin-top: 8px; }

/* ---------- Simulator ---------- */
.sim { margin-bottom: 60px; scroll-margin-top: 80px; }
.sim-grid { display: grid; grid-template-columns: 1.1fr 1fr; gap: 22px; }
.sim-controls {
    background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 26px; box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 24px;
}
.slider-top { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: 10px; }
.slider-label { display: inline-flex; align-items: center; gap: 8px; font-weight: 600; font-size: 14px; color: var(--text); }
.slider-label svg { color: var(--primary); }
.slider-val { font-size: 20px; font-weight: 800; color: var(--primary-d); }
.slider-val em { font-size: 13px; font-weight: 500; color: var(--text-mute); font-style: normal; }
.slider input[type=range] {
    -webkit-appearance: none; appearance: none; width: 100%; height: 8px; border-radius: 999px;
    background: linear-gradient(to right, var(--primary) var(--pct), var(--border) var(--pct));
    outline: none;
}
.slider input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none; appearance: none; width: 22px; height: 22px; border-radius: 50%;
    background: #fff; border: 3px solid var(--primary); cursor: pointer; box-shadow: 0 2px 6px rgba(0,0,0,.18);
}
.slider input[type=range]::-moz-range-thumb {
    width: 22px; height: 22px; border-radius: 50%; background: #fff; border: 3px solid var(--primary); cursor: pointer;
}
.sim-round { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.sim-round > span { font-weight: 600; font-size: 14px; }
.seg { display: inline-flex; background: var(--bg); border: 1px solid var(--border); border-radius: 10px; padding: 3px; }
.seg button { border: none; background: transparent; padding: 7px 12px; border-radius: 8px; font-size: 13px; font-weight: 600; color: var(--text-mute); }
.seg button.on { background: var(--panel); color: var(--primary-d); box-shadow: var(--shadow); }

.sim-result {
    background: linear-gradient(160deg, #1e3a8a, #2563eb); color: #fff;
    border-radius: var(--radius); padding: 26px; box-shadow: var(--shadow-lg);
    display: flex; flex-direction: column;
}
.sr-credits { text-align: center; padding-bottom: 18px; border-bottom: 1px solid rgba(255,255,255,.18); margin-bottom: 16px; }
.sr-label { font-size: 13px; opacity: .85; text-transform: uppercase; letter-spacing: .6px; }
.sr-big { display: flex; align-items: center; justify-content: center; gap: 10px; font-size: 46px; font-weight: 800; margin: 6px 0; }
.sr-formula { font-size: 13px; opacity: .8; }
.sr-line { display: flex; justify-content: space-between; align-items: center; padding: 7px 0; font-size: 14px; }
.sr-line b { font-size: 16px; }
.sr-line.muted { opacity: .8; font-size: 13px; }
.sr-line.save { color: #bbf7d0; }
.sim-result .btn.primary { background: #fff; color: var(--primary-d); margin-top: 16px; box-shadow: none; }
.sim-result .btn.primary:hover { background: #f1f5f9; }
.sr-hint { display: flex; align-items: center; gap: 6px; font-size: 12px; opacity: .8; margin-top: 12px; justify-content: center; text-align: center; }

/* ---------- Packs ---------- */
.packs { margin-bottom: 60px; scroll-margin-top: 80px; }
.packs-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; align-items: start; }
.pack-card {
    background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 24px 20px; box-shadow: var(--shadow); position: relative; display: flex; flex-direction: column;
}
.pack-card.featured { border-color: var(--primary); box-shadow: 0 8px 26px rgba(37,99,235,.18); transform: translateY(-6px); }
.pack-badge {
    position: absolute; top: -11px; left: 50%; transform: translateX(-50%);
    background: var(--primary); color: #fff; font-size: 11px; font-weight: 700;
    padding: 4px 12px; border-radius: 999px; white-space: nowrap;
}
.pack-card h3 { font-size: 16px; color: var(--text-mute); font-weight: 700; }
.pack-credits { display: flex; align-items: center; gap: 8px; font-size: 30px; font-weight: 800; margin: 10px 0 2px; color: var(--text); }
.pack-credits svg { color: var(--warning); }
.pack-credits span { font-size: 14px; font-weight: 500; color: var(--text-mute); }
.pack-price { font-size: 22px; font-weight: 800; color: var(--primary-d); }
.pack-rate { font-size: 12.5px; color: var(--text-mute); margin-bottom: 16px; }
.pack-feats { list-style: none; display: flex; flex-direction: column; gap: 8px; margin-bottom: 18px; flex: 1; }
.pack-feats li { display: flex; align-items: center; gap: 8px; font-size: 13px; color: var(--text); }
.pack-feats svg { color: var(--success); flex-shrink: 0; }

/* ---------- FAQ ---------- */
.faq { max-width: 760px; margin: 0 auto; }
.faq-list { display: flex; flex-direction: column; gap: 10px; }
.faq-item { background: var(--panel); border: 1px solid var(--border); border-radius: 12px; padding: 16px 18px; cursor: pointer; transition: border-color .15s; }
.faq-item:hover { border-color: var(--primary); }
.faq-item.open { border-color: var(--primary); }
.faq-q { display: flex; justify-content: space-between; align-items: center; font-weight: 600; font-size: 15px; }
.faq-chev { color: var(--primary); font-size: 22px; font-weight: 300; }
.faq-a { margin-top: 10px; font-size: 14px; color: var(--text-mute); }

/* ---------- Account ---------- */
.account { max-width: 1080px; }
.acc-top { display: grid; grid-template-columns: 340px 1fr; gap: 20px; margin-bottom: 28px; }
.balance-card {
    background: linear-gradient(160deg, #1e3a8a, #2563eb); color: #fff;
    border-radius: var(--radius); padding: 26px; box-shadow: var(--shadow-lg);
    display: flex; flex-direction: column;
}
.balance-card.low { background: linear-gradient(160deg, #7f1d1d, #dc2626); }
.bc-head { display: flex; align-items: center; gap: 8px; font-size: 13.5px; opacity: .9; }
.bc-value { font-size: 44px; font-weight: 800; margin: 8px 0 14px; }
.bc-value span { font-size: 16px; font-weight: 500; opacity: .85; }
.bc-gauge { height: 8px; border-radius: 999px; background: rgba(255,255,255,.25); overflow: hidden; }
.bc-gauge span { display: block; height: 100%; background: #fff; border-radius: 999px; transition: width .4s; }
.bc-sub { font-size: 13px; margin: 12px 0 18px; opacity: .9; }
.bc-sub .warn { display: inline-flex; align-items: center; gap: 6px; font-weight: 600; }
.balance-card .btn.primary { background: #fff; color: var(--primary-d); box-shadow: none; margin-top: auto; }
.balance-card.low .btn.primary { color: #b91c1c; }

.acc-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.stat-box { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow); position: relative; }
.sb-ico { position: absolute; top: 18px; right: 18px; width: 36px; height: 36px; border-radius: 10px; background: var(--primary-l); color: var(--primary-d); display: grid; place-items: center; }
.sb-label { font-size: 13px; color: var(--text-mute); font-weight: 600; }
.sb-value { font-size: 26px; font-weight: 800; margin-top: 4px; }
.sb-sub { font-size: 12.5px; color: var(--text-mute); }
.chart-box { grid-column: span 2; }
.mini-bars { display: flex; align-items: flex-end; gap: 10px; height: 90px; margin-top: 14px; }
.mb-col { flex: 1; display: flex; flex-direction: column; align-items: center; height: 100%; justify-content: flex-end; gap: 6px; }
.mb-bar { width: 70%; max-width: 40px; background: linear-gradient(to top, var(--primary), #60a5fa); border-radius: 6px 6px 0 0; min-height: 6px; transition: height .3s; }
.mb-lbl { font-size: 11px; color: var(--text-mute); }
.mini-empty { color: var(--text-mute); font-size: 13px; padding: 20px 0; }

/* ---------- Ledger ---------- */
.ledger { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); padding: 8px 8px 12px; box-shadow: var(--shadow); }
.ledger-head { display: flex; align-items: center; justify-content: space-between; padding: 16px 16px 10px; }
.ledger-head h2 { font-size: 18px; }
.ledger-table { display: flex; flex-direction: column; }
.ledger-row { display: flex; align-items: center; gap: 14px; padding: 13px 14px; border-radius: 12px; }
.ledger-row:hover { background: var(--bg); }
.lr-ico { width: 38px; height: 38px; border-radius: 11px; display: grid; place-items: center; flex-shrink: 0; }
.lr-ico.in { background: #dcfce7; color: #16a34a; }
.lr-ico.out { background: #eff6ff; color: var(--primary); }
.lr-main { flex: 1; min-width: 0; }
.lr-label { font-weight: 600; font-size: 14.5px; }
.lr-sub { font-size: 12.5px; color: var(--text-mute); }
.lr-credits { font-size: 16px; font-weight: 800; }
.lr-credits.in { color: #16a34a; }
.lr-credits.out { color: var(--text); }

/* ---------- Modal ---------- */
.modal-overlay { position: fixed; inset: 0; background: rgba(15,23,42,.55); backdrop-filter: blur(3px); z-index: 1000; display: grid; place-items: center; padding: 20px; }
.modal { background: var(--panel); border-radius: 20px; width: 100%; max-width: 560px; padding: 26px; box-shadow: var(--shadow-lg); animation: pop .18s ease; }
@keyframes pop { from { transform: scale(.96); opacity: 0; } to { transform: scale(1); opacity: 1; } }
.modal-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 18px; }
.modal-head h3 { font-size: 20px; }
.modal-x { border: none; background: var(--bg); width: 34px; height: 34px; border-radius: 9px; font-size: 22px; color: var(--text-mute); line-height: 1; }
.modal-x:hover { background: var(--border); }
.modal-packs { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; margin-bottom: 18px; }
.mp-item { text-align: left; background: var(--panel); border: 2px solid var(--border); border-radius: 12px; padding: 14px; transition: border-color .15s, background .15s; }
.mp-item:hover { border-color: #bfdbfe; }
.mp-item.on { border-color: var(--primary); background: #f5f9ff; }
.mp-name { font-weight: 700; font-size: 14px; display: flex; align-items: center; gap: 8px; }
.mp-name em { font-style: normal; font-size: 10.5px; font-weight: 700; background: var(--primary-l); color: var(--primary-d); padding: 2px 7px; border-radius: 999px; }
.mp-credits { font-size: 18px; font-weight: 800; margin-top: 4px; }
.mp-price { font-size: 14px; color: var(--primary-d); font-weight: 700; }
.mp-rate { font-size: 12px; color: var(--text-mute); }
.modal-summary { background: var(--bg); border-radius: 12px; padding: 14px 16px; margin-bottom: 16px; }
.ms-line { display: flex; justify-content: space-between; font-size: 14px; padding: 4px 0; }
.ms-line.total { border-top: 1px dashed var(--border); margin-top: 6px; padding-top: 10px; font-size: 16px; }
.ms-line.total b { color: var(--primary-d); }
.modal-note { display: flex; align-items: center; justify-content: center; gap: 6px; font-size: 12px; color: var(--text-mute); margin-top: 12px; }
.modal-done { text-align: center; padding: 20px 0 6px; }
.done-ico { width: 70px; height: 70px; border-radius: 50%; background: #dcfce7; color: #16a34a; display: grid; place-items: center; margin: 0 auto 16px; }
.modal-done h3 { font-size: 22px; }
.modal-done p { color: var(--text-mute); margin: 8px 0 20px; }

/* ---------- Footer ---------- */
.foot { border-top: 1px solid var(--border); background: var(--panel); padding: 20px 24px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; font-size: 12.5px; color: var(--text-mute); }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
    .principle { grid-template-columns: 1fr 1fr; }
    .packs-grid { grid-template-columns: 1fr 1fr; }
    .sim-grid { grid-template-columns: 1fr; }
    .acc-top { grid-template-columns: 1fr; }
    .pack-card.featured { transform: none; }
}
@media (max-width: 560px) {
    .hero h1 { font-size: 30px; }
    .principle, .packs-grid, .acc-stats, .modal-packs { grid-template-columns: 1fr; }
    .chart-box { grid-column: span 1; }
    .tabs { display: none; }
    .foot { flex-direction: column; }
}