:root {
    --bg: #0f172a;
    --card: #1e293b;
    --border: #334155;
    --text: #e2e8f0;
    --muted: #94a3b8;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --error: #f87171;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.5;
}

/* --- Login --- */
.login-body {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
}
.login-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 32px;
    width: 340px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}
.login-card h1 { font-size: 20px; margin: 0 0 8px; text-align: center; }

/* --- App layout (sidebar + content) --- */
.app { display: flex; min-height: 100vh; }
.sidebar {
    width: 240px;
    flex-shrink: 0;
    background: var(--card);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    padding: 20px 14px;
}
.logo { font-weight: 700; font-size: 17px; padding: 6px 10px 20px; }
.nav { display: flex; flex-direction: column; gap: 4px; flex: 1; }
.nav-item {
    display: flex;
    align-items: center;
    gap: 10px;
    background: transparent;
    color: var(--muted);
    border: none;
    border-radius: 8px;
    padding: 11px 12px;
    font-size: 14.5px;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
}
.nav-item:hover { background: var(--bg); color: var(--text); }
.nav-item.active { background: var(--accent); color: #fff; }
.nav-item .ico { width: 18px; text-align: center; font-size: 15px; }
.sidebar-foot { border-top: 1px solid var(--border); padding-top: 14px; display: flex; flex-direction: column; gap: 10px; }
.user-box { display: flex; flex-direction: column; gap: 8px; }
.user-name { color: var(--text); font-size: 14px; font-weight: 500; }
.btn-ghost.sm { padding: 6px 10px; font-size: 13px; }

.content { flex: 1; padding: 28px 32px; max-width: 1100px; }
.page-head { margin-bottom: 22px; }
.page-head h1 { font-size: 22px; margin: 0; }

.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 20px;
}
.card.narrow { max-width: 560px; }
.card h2 { margin: 0 0 16px; font-size: 17px; }
.card-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 16px; }
.card-head h2 { margin: 0; }
.hint { color: var(--muted); font-size: 13.5px; margin: 0 0 18px; }

/* --- Dashboard stats --- */
.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}
.stat-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 20px;
}
.stat-num { font-size: 30px; font-weight: 700; }
.stat-label { color: var(--muted); font-size: 13px; margin-top: 4px; }

/* --- Form --- */
label {
    display: flex;
    flex-direction: column;
    gap: 6px;
    font-size: 14px;
    color: var(--muted);
    margin-bottom: 14px;
}
.row { display: flex; gap: 16px; }
.row label { flex: 1; }
input, select, textarea {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px 12px;
    color: var(--text);
    font-size: 15px;
    font-family: inherit;
}
input:focus, select:focus, textarea:focus { outline: none; border-color: var(--accent); }
input[readonly], textarea[readonly] { color: var(--muted); }
textarea { resize: vertical; width: 100%; }
#keyOutBig { font-family: ui-monospace, "Cascadia Code", monospace; margin-top: 8px; }

button {
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: 8px;
    padding: 10px 18px;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
}
button:hover { background: var(--accent-hover); }
.btn-ghost {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text);
    padding: 6px 14px;
    font-size: 14px;
}
.btn-ghost:hover { background: var(--border); }

/* --- Result --- */
.result { margin-top: 20px; }
.key-out { display: flex; gap: 8px; }
.key-out input {
    flex: 1;
    font-family: ui-monospace, "Cascadia Code", monospace;
    font-size: 18px;
    letter-spacing: 1px;
}

.error { color: var(--error); font-size: 14px; margin: 12px 0 0; min-height: 1em; }

/* --- Filter bar (lịch sử) --- */
.filter-bar { display: flex; gap: 10px; margin-bottom: 18px; }
.filter-bar input { flex: 1; margin: 0; }
.filter-bar select { margin: 0; }
.filter-bar button { flex-shrink: 0; }
.empty { color: var(--muted); text-align: center; padding: 24px 0; }

/* --- Verify output --- */
.verify-out { margin-top: 20px; display: flex; flex-direction: column; gap: 10px; }
.vrow { display: flex; justify-content: space-between; gap: 16px; padding: 10px 14px; background: var(--bg); border-radius: 8px; }
.vrow span { color: var(--muted); font-size: 14px; }
.vrow b { word-break: break-all; text-align: right; }
.badge { padding: 10px 14px; border-radius: 8px; font-weight: 600; text-align: center; }
.badge.ok { background: rgba(34,197,94,0.15); color: #4ade80; }
.badge.bad { background: rgba(248,113,113,0.15); color: var(--error); }

/* --- History --- */
.history { width: 100%; border-collapse: collapse; font-size: 14px; }
.history th, .history td {
    text-align: left;
    padding: 8px 10px;
    border-bottom: 1px solid var(--border);
}
.history th { color: var(--muted); font-weight: 500; }
.mono { font-family: ui-monospace, "Cascadia Code", monospace; }

/* --- Modal đổi mật khẩu --- */
.modal-overlay[hidden] { display: none; }
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 50;
}
.modal-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 28px;
    width: 360px;
    max-width: calc(100vw - 32px);
}
.modal-card h2 { margin: 0 0 18px; font-size: 18px; }
.modal-actions { display: flex; justify-content: flex-end; gap: 10px; margin-top: 8px; }