:root {
    --army-900: #081c15;
    --army-800: #1b4332;
    --army-700: #2d6a4f;
    --army-600: #40916c;
    --army-500: #52b788;
    --army-100: #d8f3dc;
    --army-gold: #cba135;
    --sidebar-w: 250px;
    --sidebar-mini: 72px;
    --topbar-h: 58px;
    --surface: #f4f7f5;
    --line: #e2e8e5;
}

* { box-sizing: border-box; }

html, body {
    margin: 0;
    font-family: 'Sarabun', 'Segoe UI', Tahoma, sans-serif;
    background: var(--surface);
    color: #1f2a26;
    -webkit-text-size-adjust: 100%;
}

h1, h2, h3, h4, h5 { font-weight: 600; }
h1:focus {
outline:none;
}

/* ============ Buttons ============ */
.btn-army {
    background: var(--army-700);
    border-color: var(--army-700);
    color: #fff;
}
.btn-army:hover, .btn-army:focus { background: var(--army-800); border-color: var(--army-800); color: #fff; }
.btn-army-outline { border: 1px solid var(--army-700); color: var(--army-700); background: transparent; }
.btn-army-outline:hover { background: var(--army-700); color: #fff; }

.btn-icon {
    background: transparent; border: none; color: #fff;
    width: 40px; height: 40px; border-radius: 10px;
    display: inline-flex; align-items: center; justify-content: center;
    font-size: 1.25rem; cursor: pointer; transition: background .15s;
}
.btn-icon:hover { background: rgba(255,255,255,.15); }
.btn-icon-light { color: #fff; text-decoration: none; font-size: 1.25rem; }

a { color: var(--army-700); }

/* ============ App shell (staff) ============ */
.nav-toggle-input { position: absolute; opacity: 0; width: 0; height: 0; pointer-events: none; }
.app-shell { min-height: 100vh; }

.sidebar {
    position: fixed; top: 0; left: 0; bottom: 0; z-index: 1040;
    width: var(--sidebar-w);
    background: linear-gradient(180deg, var(--army-900), var(--army-800));
    color: #d8f3dc;
    display: flex; flex-direction: column;
    transition: width .2s ease, transform .25s ease;
    overflow: hidden;
}
.sidebar-brand {
    height: var(--topbar-h);
    display: flex; align-items: center; gap: .6rem;
    padding: 0 1rem; color: #fff; font-weight: 700; font-size: 1.15rem;
    border-bottom: 1px solid rgba(255,255,255,.08);
    white-space: nowrap;
}
.brand-icon { color: var(--army-gold); font-size: 1.5rem; }
.sidebar-nav { flex: 1; padding: .75rem .5rem; display: flex; flex-direction: column; gap: .25rem; }
.sidebar-footer { padding: .5rem; border-top: 1px solid rgba(255,255,255,.08); }

.nav-item-link {
    display: flex; align-items: center; gap: .85rem;
    padding: .7rem .85rem; border-radius: 10px;
    color: #c7e6d3; text-decoration: none; white-space: nowrap;
    font-weight: 500; transition: background .15s, color .15s;
}
.nav-item-link i { font-size: 1.2rem; min-width: 1.2rem; text-align: center; }
.nav-item-link:hover { background: rgba(255,255,255,.10); color: #fff; }
.nav-item-link.active { background: var(--army-600); color: #fff; }

.app-main {
    margin-left: var(--sidebar-w);
    transition: margin-left .2s ease;
    min-height: 100vh; display: flex; flex-direction: column;
}

/* Collapsed (desktop mini) — เมื่อ checkbox ถูกติ๊ก */
.nav-toggle-input:checked ~ .app-shell .sidebar { width: var(--sidebar-mini); }
.nav-toggle-input:checked ~ .app-shell .brand-text,
.nav-toggle-input:checked ~ .app-shell .nav-text { opacity: 0; width: 0; pointer-events: none; }
.nav-toggle-input:checked ~ .app-shell .nav-item-link { justify-content: center; }
.nav-toggle-input:checked ~ .app-shell .app-main { margin-left: var(--sidebar-mini); }

.topbar {
    position: sticky; top: 0; z-index: 1030;
    height: var(--topbar-h);
    background: var(--army-800);
    color: #fff; display: flex; align-items: center; gap: .5rem;
    padding: 0 .75rem; box-shadow: 0 2px 8px rgba(0,0,0,.12);
}
.topbar-title { font-weight: 600; font-size: 1.05rem; flex: 1; }
.topbar-right { display: flex; align-items: center; gap: .4rem; }
.user-chip { display: inline-flex; align-items: center; gap: .4rem; font-size: .9rem; }

.app-content { padding: 1.25rem; flex: 1; }

/* Backdrop for mobile overlay */
.backdrop {
    position: fixed; inset: 0; background: rgba(0,0,0,.45);
    z-index: 1035; opacity: 0; visibility: hidden; transition: opacity .2s;
}

/* ============ Mobile (< 992px) ============ */
@media (max-width: 991.98px) {
    /* บนมือถือ: sidebar เป็นแบบสไลด์ทับ (off-canvas) เริ่มต้นซ่อน */
    .sidebar { transform: translateX(-100%); width: var(--sidebar-w); }
    .app-main { margin-left: 0 !important; }

    /* checkbox ติ๊ก = เปิดเมนูสไลด์ */
    .nav-toggle-input:checked ~ .app-shell .sidebar { transform: translateX(0); width: var(--sidebar-w); }
    .nav-toggle-input:checked ~ .app-shell .backdrop { opacity: 1; visibility: visible; }

    /* บนมือถือให้แสดง label เสมอ (ไม่ย่อเป็นไอคอน) */
    .nav-toggle-input:checked ~ .app-shell .brand-text,
    .nav-toggle-input:checked ~ .app-shell .nav-text { opacity: 1; width: auto; pointer-events: auto; }
    .nav-toggle-input:checked ~ .app-shell .nav-item-link { justify-content: flex-start; }

    .app-content { padding: 1rem .85rem; }
}

/* ============ Cards / tables ============ */
.card-army { border: 1px solid var(--line); border-radius: 14px; background: #fff; box-shadow: 0 1px 3px rgba(16,44,32,.05); }
.page-head { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-bottom: 1rem; flex-wrap: wrap; }
.page-head h1 { font-size: 1.4rem; margin: 0; color: var(--army-800); }

.table thead th { background: var(--army-100); color: var(--army-800); border-bottom: 2px solid var(--army-600); white-space: nowrap; }
.table-hover tbody tr:hover { background: #f0f7f3; }
.badge-army { background: var(--army-600); color: #fff; }

/* ============ Forms ============ */
.form-label { font-weight: 500; color: #33403a; margin-bottom: .25rem; }
.form-control:focus, .form-select:focus { border-color: var(--army-600); box-shadow: 0 0 0 .2rem rgba(64,145,108,.2); }
.section-title { font-weight: 600; color: var(--army-800); border-left: 4px solid var(--army-600); padding-left: .6rem; margin: 1rem 0 .75rem; }

/* ============ Empty / login shell ============ */
.empty-shell { min-height: 100vh; display: flex; align-items: center; justify-content: center; padding: 1rem;
    background: radial-gradient(1200px 600px at 20% -10%, var(--army-700), var(--army-900)); }
.login-card { width: 100%; max-width: 420px; background: #fff; border-radius: 18px; padding: 1.75rem; box-shadow: 0 18px 45px rgba(0,0,0,.3); }
.login-logo { width: 64px; height: 64px; border-radius: 16px; background: var(--army-700); color: var(--army-gold);
    display: flex; align-items: center; justify-content: center; font-size: 2rem; margin: 0 auto .75rem; }

/* ============ Student (mobile-first) shell ============ */
.student-shell { min-height: 100vh; display: flex; flex-direction: column; background: var(--surface); }
.student-topbar { background: linear-gradient(90deg, var(--army-800), var(--army-700)); color: #fff; position: sticky; top: 0; z-index: 20; }
.student-topbar-inner { max-width: 720px; margin: 0 auto; height: 54px; display: flex; align-items: center; justify-content: space-between; padding: 0 1rem; }
.student-brand { font-weight: 700; }
.student-content { flex: 1; width: 100%; max-width: 720px; margin: 0 auto; padding: 1rem; }
.student-footer { text-align: center; color: #7a8a83; font-size: .85rem; padding: 1rem; }

.field-card { background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: 1rem; margin-bottom: 1rem; }
.field-card h5 { color: var(--army-800); font-size: 1rem; margin-bottom: .85rem; }

.readonly-chip { background: var(--army-100); color: var(--army-800); border-radius: 8px; padding: .5rem .75rem; font-weight: 500; }

/* Toast / alert */
.alert-army { background: var(--army-100); color: var(--army-800); border: 1px solid var(--army-500); }

/* validation */
.validation-message { color: #d6336c; font-size: .85rem; }
.valid.modified:not([type=checkbox]) { outline: none; }
.invalid { border-color: #d6336c !important; }

/* ============ ThaiDatePicker (วัน/เดือน/ปี พ.ศ.) ============ */
.th-picker { display: flex; gap: .5rem; }
.th-picker .input {
    -webkit-appearance: none; -moz-appearance: none; appearance: none;
    display: block; width: 100%;
    padding: .5rem 2rem .5rem .75rem;
    font-size: 1rem; line-height: 1.5;
    color: var(--army-900, #081c15);
    background-color: #fff;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3e%3cpath fill='none' stroke='%232d6a4f' stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='m2 5 6 6 6-6'/%3e%3c/svg%3e");
    background-repeat: no-repeat; background-position: right .6rem center; background-size: 14px 11px;
    border: 1px solid #ced4da; border-radius: .5rem;
    transition: border-color .15s ease, box-shadow .15s ease;
    cursor: pointer;
}
.th-picker .input:focus {
    outline: 0; border-color: var(--army-600, #40916c);
    box-shadow: 0 0 0 .2rem rgba(64, 145, 108, .25);
}
.th-picker-day   { flex: 0 0 22%; }
.th-picker-month { flex: 1 1 auto; }
.th-picker-year  { flex: 0 0 30%; }

@media (max-width: 400px) {
    .th-picker { gap: .35rem; }
    .th-picker .input { padding: .5rem 1.6rem .5rem .5rem; font-size: .95rem; }
}