/* =========================================================
   BtSh – Login Page (Enterprise Grade)
   Desktop-first, mobile-friendly
========================================================= */

:root {
    --bg: #f5f7fb;
    --card: #ffffff;
    --text: #0f172a;
    --muted: #64748b;
    --border: #e2e8f0;
    --primary: #2563eb;
    --primary-dark: #1e40af;
    --danger: #dc2626;
    --radius: 12px;
    --shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
    --font: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
}

/* ===== Layout ===== */

.login-shell {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    min-height: 100vh;
}

/* ===== Brand Side ===== */

.login-brand {
    position: relative;
    overflow: hidden;
}

.login-brand img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.login-brand .overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(to bottom,
            rgba(0, 0, 0, 0.65),
            rgba(0, 0, 0, 0.85));
    color: #ffffff;
    padding: 48px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    font-size: 16px;
    line-height: 1.5;
}

.btsh-auth-logo img {
    width: 120px;
    margin-bottom: 20px;
}

/* ===== Form Side ===== */

.login-form {
    background: var(--card);
    padding: 64px 56px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    box-shadow: -12px 0 40px rgba(0, 0, 0, 0.05);
}

.login-form h2 {
    margin: 0 0 6px;
    font-size: 28px;
}

.login-form .sub {
    margin-bottom: 32px;
    color: var(--muted);
}

/* ===== Fields ===== */

.field {
    margin-bottom: 18px;
}

.field label {
    display: block;
    font-size: 14px;
    margin-bottom: 6px;
    color: #334155;
}

.field input {
    width: 100%;
    padding: 12px 14px;
    border-radius: 8px;
    border: 1px solid var(--border);
    font-size: 15px;
    background: #ffffff;
}

.field input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

/* ===== Buttons ===== */

.btn {
    width: 100%;
    padding: 13px;
    border-radius: 10px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    border: none;
}

.btn.primary {
    background: var(--primary);
    color: #ffffff;
}

.btn.primary:hover {
    background: var(--primary-dark);
}

/* ===== Links & Meta ===== */

.auth-row {
    margin: 16px 0;
    text-align: right;
}

.auth-link {
    font-size: 14px;
    color: var(--primary);
    text-decoration: none;
}

.auth-link:hover {
    text-decoration: underline;
}

.alt {
    margin-top: 28px;
    font-size: 14px;
    color: var(--muted);
}

.alt a {
    color: var(--primary);
    text-decoration: none;
}

.legal {
    margin-top: 24px;
    font-size: 12px;
    color: var(--muted);
    line-height: 1.6;
}

.legal a {
    color: var(--primary);
    text-decoration: none;
}

/* ===== Error ===== */

.error {
    margin-top: 14px;
    color: var(--danger);
    font-size: 14px;
    min-height: 18px;
}

/* ===== Responsive ===== */

@media (max-width: 900px) {
    .login-shell {
        grid-template-columns: 1fr;
    }

    .login-brand {
        display: none;
    }

    .login-form {
        box-shadow: none;
        padding: 48px 24px;
    }
}