:root {
    --bg-color: var(--ui-bg);
    --text-primary: var(--ui-text);
    --text-secondary: var(--ui-text-muted);
    --accent-color: var(--ui-accent);
    --input-bg: var(--ui-surface);
    --input-focus-bg: var(--ui-surface-solid);
    --border-color: var(--ui-border);
    --button-bg: var(--ui-accent);
    --button-hover: var(--ui-accent-strong);
}

body {
    font-family: var(--font-body);
    background:
        radial-gradient(880px at 12% 12%, var(--ui-ambient-1), transparent 60%),
        radial-gradient(820px at 86% 80%, var(--ui-ambient-2), transparent 62%),
        linear-gradient(160deg, var(--ui-bg-alt), var(--bg-color));
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
    box-sizing: border-box;
    position: relative;
}

.main-wrapper {
    width: 100%;
    max-width: 380px;
    display: flex;
    flex-direction: column;
    align-items: center;
    background: var(--ui-surface);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    padding: 3.2rem 2.4rem 2.6rem;
    box-shadow: var(--ui-shadow);
    backdrop-filter: blur(16px);
}

.logo-area {
    margin-bottom: 2rem;
    text-align: center;
    position: relative;
    padding-top: 3.2rem;
}

.logo-area::before {
    content: "AI";
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 46px;
    height: 46px;
    border-radius: 14px;
    background: linear-gradient(140deg, var(--accent-color), var(--button-hover));
    color: #f8fafc;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    box-shadow: 0 12px 24px rgba(123, 141, 163, 0.28);
}

.logo-area h1 {
    font-size: 1.6rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
    letter-spacing: 0.04em;
    font-family: var(--font-display);
}

.logo-area p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

form {
    width: 100%;
}

.form-container {
    display: none;
}

.form-container.active {
    display: block;
}

.input-group {
    margin-bottom: 1.2rem;
    position: relative;
}

.input-group.inline-group {
    display: flex;
    gap: 0.5rem;
}

.input-group.inline-group .input-flex {
    flex: 1;
}

.input-group input {
    width: 100%;
    padding: 0.95rem 1rem;
    padding-right: 2.8rem;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background-color: var(--input-bg);
    color: var(--text-primary);
    box-sizing: border-box;
    font-size: 1rem;
    outline: none;
    transition: all 0.3s ease;
    text-align: left;
    box-shadow: inset 0 1px 2px rgba(15, 23, 42, 0.05);
}

.input-group input:focus {
    background-color: var(--input-focus-bg);
    border-color: var(--accent-color);
    box-shadow: 0 6px 16px rgba(15, 23, 42, 0.08);
    transform: translateY(-1px);
}

.password-toggle {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 1.1rem;
    padding: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.2s ease;
}

.password-toggle:hover {
    color: var(--accent-color);
}

.password-toggle svg {
    width: 18px;
    height: 18px;
}

.input-group.has-password-toggle input {
    padding-right: 2.8rem;
}

.action-btn {
    width: 100%;
    padding: 1rem;
    background: linear-gradient(140deg, var(--button-bg), var(--button-hover));
    color: #f8fafc;
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    margin-top: 1rem;
    letter-spacing: 0.08em;
}

.action-btn.send-code-btn {
    width: auto;
    padding: 1rem 1.5rem;
    margin: 0;
    white-space: nowrap;
}

.action-btn:hover {
    background: linear-gradient(140deg, var(--button-hover), var(--button-bg));
    transform: translateY(-2px);
    box-shadow: 0 14px 28px rgba(123, 141, 163, 0.32);
}

#message-box {
    margin-top: 1.5rem;
    text-align: center;
    font-size: 0.9rem;
    min-height: 1.2em;
    color: var(--accent-color);
}

.error { color: var(--ui-danger) !important; }
.success { color: var(--ui-success) !important; }

.secondary-actions {
    margin-top: 2rem;
    text-align: center;
}

.secondary-actions a {
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-decoration: none;
    cursor: pointer;
}
.secondary-actions a:hover {
    color: var(--accent-color);
}

.secondary-actions span {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* OAuth 登录按钮样式 */
.oauth-login-section {
    width: 100%;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.oauth-helper {
    text-align: center;
    margin-bottom: 1rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.oauth-btn {
    width: 100%;
    padding: 0.9rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 50px;
    background-color: var(--ui-surface-solid);
    color: var(--text-primary);
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
}

.oauth-btn + .oauth-btn {
    margin-top: 0.8rem;
}

.oauth-btn:hover {
    background-color: var(--ui-highlight);
    border-color: var(--accent-color);
    transform: translateY(-1px);
    box-shadow: 0 10px 20px rgba(15, 23, 42, 0.16);
}

.oauth-btn.github-btn:hover {
    background-color: #2f3135;
    color: #f8fafc;
    border-color: #2f3135;
}

.oauth-icon {
    flex-shrink: 0;
}