/* ========== Layout ========== */
:root {
    --c-bg: #f5f7fa;
    --c-card: #ffffff;
    --c-border: #e3e8ee;
    --c-primary: #2563eb;
    --c-primary-dark: #1d4ed8;
    --c-text: #1f2937;
    --c-muted: #6b7280;
    --c-success: #16a34a;
    --c-warn: #d97706;
    --c-error: #dc2626;
    --c-bg-success: #dcfce7;
    --c-bg-warn: #fef3c7;
    --c-bg-error: #fee2e2;
    --r: 8px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: var(--c-bg);
    color: var(--c-text);
    line-height: 1.45;
    font-size: 14px;
}

a { color: var(--c-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: 1200px; margin: 0 auto; padding: 1rem; }

/* ========== Header ========== */
.app-header {
    background: var(--c-card);
    border-bottom: 1px solid var(--c-border);
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    gap: 1.5rem;
    flex-wrap: wrap;
}
.app-header .brand { font-weight: 700; font-size: 1.1rem; color: var(--c-primary); }
.app-header nav { display: flex; gap: 0.25rem; flex-wrap: wrap; flex: 1; }
.app-header nav a {
    padding: 0.4rem 0.75rem;
    border-radius: var(--r);
    color: var(--c-text);
    font-weight: 500;
}
.app-header nav a:hover { background: var(--c-bg); text-decoration: none; }
.app-header nav a.active { background: var(--c-primary); color: #fff; }
.app-header .user { color: var(--c-muted); font-size: 0.9rem; }

/* ========== Cards / Tables / Forms ========== */
.card {
    background: var(--c-card);
    border: 1px solid var(--c-border);
    border-radius: var(--r);
    padding: 1.25rem;
    margin-bottom: 1rem;
}
.card h1, .card h2, .card h3 { margin-top: 0; }

table.data {
    width: 100%;
    border-collapse: collapse;
    background: var(--c-card);
}
table.data th, table.data td {
    padding: 0.5rem 0.75rem;
    border-bottom: 1px solid var(--c-border);
    text-align: left;
    vertical-align: top;
}
table.data th {
    background: #f9fafb;
    font-weight: 600;
    font-size: 0.85rem;
    text-transform: uppercase;
    color: var(--c-muted);
    letter-spacing: 0.03em;
}
table.data tr:hover td { background: #f9fafb; }
table.data td.right, table.data th.right { text-align: right; }
table.data td.center, table.data th.center { text-align: center; }

.form-row { display: flex; gap: 1rem; flex-wrap: wrap; margin-bottom: 0.75rem; }
.form-row > * { flex: 1; min-width: 200px; }
label { display: block; font-weight: 500; margin-bottom: 0.25rem; font-size: 0.85rem; }
label.inline { display: inline-block; margin-right: 1rem; }

input[type=text], input[type=email], input[type=password], input[type=number],
input[type=date], input[type=tel], select, textarea {
    width: 100%;
    padding: 0.5rem 0.625rem;
    border: 1px solid var(--c-border);
    border-radius: var(--r);
    background: #fff;
    font: inherit;
    color: inherit;
}
input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--c-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
}
textarea { min-height: 80px; resize: vertical; }

.btn {
    display: inline-block;
    padding: 0.5rem 1rem;
    border: 1px solid var(--c-border);
    border-radius: var(--r);
    background: #fff;
    color: var(--c-text);
    font: inherit;
    cursor: pointer;
    text-decoration: none;
}
.btn:hover { background: var(--c-bg); text-decoration: none; }
.btn.primary { background: var(--c-primary); color: #fff; border-color: var(--c-primary); }
.btn.primary:hover { background: var(--c-primary-dark); }
.btn.danger { background: var(--c-error); color: #fff; border-color: var(--c-error); }
.btn.small { padding: 0.25rem 0.5rem; font-size: 0.85rem; }

/* ========== Badges / Flash ========== */
.badge {
    display: inline-block;
    padding: 0.15rem 0.55rem;
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 600;
    background: #e5e7eb;
    color: #374151;
}
.badge.draft   { background: #e5e7eb; color: #374151; }
.badge.sent    { background: #dbeafe; color: #1d4ed8; }
.badge.paid    { background: var(--c-bg-success); color: #166534; }
.badge.overdue { background: var(--c-bg-error); color: #991b1b; }
.badge.cancel  { background: #fef3c7; color: #92400e; }

.flash { padding: 0.75rem 1rem; border-radius: var(--r); margin-bottom: 0.75rem; }
.flash.success { background: var(--c-bg-success); color: #166534; }
.flash.error   { background: var(--c-bg-error); color: #991b1b; }
.flash.info    { background: #dbeafe; color: #1d4ed8; }

.toolbar { display: flex; gap: 0.5rem; align-items: center; margin-bottom: 1rem; flex-wrap: wrap; }
.toolbar .spacer { flex: 1; }

/* ========== Login ========== */
.login-page { display: flex; align-items: center; justify-content: center; min-height: 100vh; padding: 1rem; }
.login-card { background: #fff; border-radius: 12px; padding: 2rem; width: 100%; max-width: 420px; box-shadow: 0 4px 18px rgba(0,0,0,0.08); }

.muted { color: var(--c-muted); }
.text-right { text-align: right; }
.mt-1 { margin-top: 0.5rem; } .mt-2 { margin-top: 1rem; } .mt-3 { margin-top: 1.5rem; }
.mb-0 { margin-bottom: 0; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
@media (max-width: 700px) { .grid-2 { grid-template-columns: 1fr; } }