:root {
    --background: hsl(222.2, 84%, 4.9%);
    --foreground: hsl(210, 40%, 98%);
    --card: hsl(222.2, 47%, 7%);
    --card-border: hsl(217.2, 32.6%, 17.5%);
    --primary: hsl(217.2, 91.2%, 59.8%);
    --primary-hover: hsl(217.2, 91.2%, 52%);
    --primary-foreground: hsl(222.2, 47.4%, 11.2%);
    --secondary: hsl(217.2, 32.6%, 17.5%);
    --muted-foreground: hsl(215, 20.2%, 65.1%);
    --input-bg: hsl(217.2, 32.6%, 17.5%);
    --input-border: hsl(217.2, 32.6%, 22%);
    --input-focus: hsl(217.2, 91.2%, 59.8%);
    --error: hsl(0, 72%, 51%);
    --header-bg: hsl(222.2, 47%, 8%);
    --header-border: hsl(217.2, 32.6%, 17.5%);
    --radius: 0.5rem;
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--background);
    color: var(--foreground);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    font-size: 14px;
    line-height: 1.5;
    min-height: 100vh;
}

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

a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* Header */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 50;
    height: 56px;
    background-color: var(--header-bg);
    border-bottom: 1px solid var(--header-border);
    display: flex;
    align-items: center;
}

.site-header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    max-width: 1152px;
    margin: 0 auto;
    padding: 0 24px;
}

.site-brand {
    font-size: 18px;
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--foreground);
    text-decoration: none;
}

.site-brand:hover {
    color: hsl(210, 40%, 90%);
    text-decoration: none;
}

.site-user {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 13px;
    color: var(--muted-foreground);
}

.site-user a {
    color: var(--muted-foreground);
    transition: color 0.15s;
}

.site-user a:hover {
    color: var(--foreground);
    text-decoration: none;
}

/* Main content */
.site-main {
    padding-top: 56px;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Auth card */
.auth-card {
    width: 100%;
    max-width: 400px;
    margin: 40px 16px;
    background-color: var(--card);
    border: 1px solid var(--card-border);
    border-radius: var(--radius);
    padding: 32px;
}

.auth-title {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 4px;
    color: var(--foreground);
}

.auth-subtitle {
    font-size: 13px;
    color: var(--muted-foreground);
    margin-bottom: 24px;
}

/* Form elements */
.form-group {
    margin-bottom: 16px;
}

.form-group label:not(.form-check) {
    display: block;
    font-size: 13px;
    font-weight: 500;
    color: var(--foreground);
    margin-bottom: 6px;
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group input[type="password"] {
    width: 100%;
    padding: 8px 12px;
    background-color: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: var(--radius);
    color: var(--foreground);
    font-size: 14px;
    outline: none;
    transition: border-color 0.15s;
}

.form-group input:focus {
    border-color: var(--input-focus);
    box-shadow: 0 0 0 2px hsl(217.2, 91.2%, 59.8%, 0.2);
}

.form-group input::placeholder {
    color: var(--muted-foreground);
}

.form-check {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: var(--muted-foreground);
    cursor: pointer;
    user-select: none;
}

.form-check input[type="checkbox"] {
    appearance: none;
    -webkit-appearance: none;
    width: 15px;
    height: 15px;
    min-width: 15px;
    border: 1px solid var(--input-border);
    border-radius: 3px;
    background-color: var(--input-bg);
    cursor: pointer;
    display: grid;
    place-items: center;
}

.form-check input[type="checkbox"]:checked {
    background-color: var(--primary);
    border-color: var(--primary);
}

.form-check input[type="checkbox"]:checked::after {
    content: '';
    width: 8px;
    height: 5px;
    border-left: 2px solid var(--primary-foreground);
    border-bottom: 2px solid var(--primary-foreground);
    transform: rotate(-45deg) translateY(-1px);
}

/* Buttons */
.btn-row {
    display: flex;
    gap: 8px;
    margin-top: 24px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 8px 16px;
    border-radius: var(--radius);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    border: none;
    transition: background-color 0.15s, color 0.15s;
    text-decoration: none;
}

.btn-primary {
    background-color: var(--primary);
    color: var(--primary-foreground);
    flex: 1;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    color: var(--primary-foreground);
    text-decoration: none;
}

.btn-ghost {
    background-color: transparent;
    color: var(--muted-foreground);
    border: 1px solid var(--card-border);
}

.btn-ghost:hover {
    background-color: var(--secondary);
    color: var(--foreground);
    text-decoration: none;
}

/* Divider */
.auth-divider {
    margin: 20px 0;
    text-align: center;
    font-size: 12px;
    color: var(--muted-foreground);
    position: relative;
}

.auth-divider::before,
.auth-divider::after {
    content: '';
    position: absolute;
    top: 50%;
    width: calc(50% - 20px);
    height: 1px;
    background-color: var(--card-border);
}

.auth-divider::before { left: 0; }
.auth-divider::after { right: 0; }

/* Footer link */
.auth-footer {
    margin-top: 20px;
    text-align: center;
    font-size: 13px;
    color: var(--muted-foreground);
}

/* Validation */
.validation-summary-valid {
    display: none;
}

.validation-summary-errors {
    background-color: hsl(0, 62.8%, 10%);
    border: 1px solid hsl(0, 62.8%, 25%);
    border-radius: var(--radius);
    padding: 10px 14px;
    margin-bottom: 16px;
    font-size: 13px;
    color: hsl(0, 72%, 70%);
}

.validation-summary-errors ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.field-validation-error {
    font-size: 12px;
    color: hsl(0, 72%, 60%);
    margin-top: 4px;
    display: block;
}

/* External providers */
.external-providers {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 8px;
}

.btn-external {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 8px 16px;
    background-color: var(--secondary);
    color: var(--foreground);
    border: 1px solid var(--card-border);
    border-radius: var(--radius);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: background-color 0.15s;
}

.btn-external:hover {
    background-color: hsl(217.2, 32.6%, 22%);
    color: var(--foreground);
    text-decoration: none;
}