/* ============================================================
   入口页（学生 / 教师）· 见 DESIGN.md
   依赖 static/css/tokens.css 中的 --ds-login-* 令牌
   ============================================================ */

* {
    box-sizing: border-box;
}

body.login-page {
    margin: 0;
    background: var(--ds-login-bg);
    color: var(--ds-login-ink-2);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
    font-size: 14px;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

@keyframes login-rise {
    from {
        opacity: 0;
        transform: translateY(12px);
    }

    to {
        opacity: 1;
        transform: none;
    }
}

/* --------------------------------------------------------------------------
   版面
   -------------------------------------------------------------------------- */

.login-stage {
    display: grid;
    grid-template-columns: minmax(0, 1fr) var(--ds-login-card-w);
    grid-template-rows: auto 1fr auto;
    column-gap: clamp(48px, 8vw, 136px);
    max-width: 1320px;
    min-height: 100vh;
    margin: 0 auto;
    padding: 0 clamp(32px, 5vw, 64px) 52px;
}

/* --------------------------------------------------------------------------
   顶栏
   -------------------------------------------------------------------------- */

.login-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    grid-column: 1 / -1;
    padding: 26px 0 16px;
    border-bottom: 1px solid var(--ds-login-line);
}

.login-brand {
    display: flex;
    align-items: center;
    gap: 11px;
    color: var(--ds-login-ink);
    font-size: 18px;
    font-weight: 600;
    letter-spacing: 0.04em;
}

.login-brand__mark {
    display: grid;
    place-items: center;
    width: 30px;
    height: 30px;
    border-radius: 9px;
    background: var(--ds-login-action);
    color: #ffffff;
    font-size: 14px;
    font-weight: 600;
    line-height: 1;
}

/* --------------------------------------------------------------------------
   左栏
   -------------------------------------------------------------------------- */

.login-intro {
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 56px 0;
}

.login-intro > div {
    animation: login-rise 0.7s cubic-bezier(0.2, 0.7, 0.3, 1) both;
}

.login-title {
    margin: 0;
    color: var(--ds-login-ink);
    font-size: 58px;
    font-weight: 600;
    line-height: 1.1;
    letter-spacing: 0;
}

.login-lede {
    max-width: 22em;
    margin: 20px 0 0;
    color: var(--ds-login-ink-2);
    font-size: 15px;
    line-height: 1.8;
}

/* --------------------------------------------------------------------------
   卡片
   -------------------------------------------------------------------------- */

.login-panel-wrap {
    align-self: center;
    display: flex;
    animation: login-rise 0.9s 0.08s cubic-bezier(0.2, 0.7, 0.3, 1) both;
}

.login-panel {
    width: 100%;
    padding: 34px 32px 30px;
    border: 1px solid var(--ds-login-border-strong);
    border-top: 3px solid var(--ds-login-action);
    border-radius: var(--ds-login-radius-card);
    background: var(--ds-login-card);
    box-shadow: 0 12px 32px rgba(23, 64, 120, 0.08);
}

/* --------------------------------------------------------------------------
   表单
   -------------------------------------------------------------------------- */

.login-form {
    margin: 0;
    counter-reset: login-field;
}

.login-field + .login-field {
    margin-top: 20px;
}

.login-field__head {
    display: flex;
    align-items: baseline;
    gap: 9px;
    margin-bottom: 7px;
}

.login-field__index::before {
    counter-increment: login-field;
    content: counter(login-field, decimal-leading-zero);
}

.login-field__index {
    color: var(--ds-login-accent-ink);
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 10px;
    font-variant-numeric: tabular-nums;
    letter-spacing: 0.1em;
}

.login-field__label {
    color: var(--ds-login-ink-2);
    font-size: 13px;
    font-weight: 500;
}

.login-control {
    display: block;
    width: 100%;
    height: var(--ds-login-control-h);
    padding: 0 36px 0 13px;
    border: 1px solid var(--ds-login-border);
    border-radius: var(--ds-login-radius);
    background: #ffffff;
    color: var(--ds-login-ink);
    font-family: inherit;
    font-size: 14px;
    line-height: 1.4;
    transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.login-control::placeholder {
    color: var(--ds-login-placeholder);
    opacity: 1;
}

.login-control:hover {
    border-color: #a9bdd3;
}

.login-control:focus {
    outline: none;
    border-color: var(--ds-login-focus);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.18);
}

.login-control.is-invalid {
    border-color: var(--ds-login-danger);
    box-shadow: 0 0 0 3px rgba(192, 57, 43, 0.12);
}

select.login-control {
    appearance: none;
    -webkit-appearance: none;
    background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1.5 6 6.5l5-5' fill='none' stroke='%2364788f' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 13px center;
    cursor: pointer;
}

.login-field__error {
    margin: 7px 0 0;
    color: var(--ds-login-danger);
    font-size: 12px;
    line-height: 1.5;
}

/* 密码框 + 眼睛按钮 */
.login-control-wrap {
    position: relative;
}

.login-control-wrap .login-control {
    padding-right: 48px;
}

.login-eye {
    position: absolute;
    top: 50%;
    right: 6px;
    display: grid;
    place-items: center;
    width: 34px;
    height: 34px;
    padding: 0;
    border: 0;
    border-radius: 8px;
    background: transparent;
    transform: translateY(-50%);
    cursor: pointer;
}

.login-eye:hover {
    background: #f2f7fd;
}

.login-eye:focus-visible {
    outline: none;
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.18);
}

.login-eye img {
    display: block;
    width: 18px;
    height: 18px;
}

/* 记住我 */
.login-check {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-top: 16px;
    color: var(--ds-login-ink-2);
    font-size: 13px;
    line-height: 1.4;
}

.login-check input {
    width: 16px;
    height: 16px;
    margin: 0;
    accent-color: var(--ds-login-action);
    cursor: pointer;
}

.login-check label {
    cursor: pointer;
}

/* 主按钮 */
.login-submit {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
    height: var(--ds-login-submit-h);
    margin-top: 26px;
    padding: 0 20px;
    border: 0;
    border-radius: var(--ds-login-radius);
    background: var(--ds-login-action);
    box-shadow: 0 8px 18px rgba(0, 105, 217, 0.22);
    color: #ffffff;
    font-family: inherit;
    font-size: 15px;
    font-weight: 500;
    line-height: 1;
    cursor: pointer;
    transition: background-color 0.18s ease, box-shadow 0.18s ease;
}

.login-submit:hover {
    background: var(--ds-login-action-hover);
    box-shadow: 0 10px 22px rgba(0, 98, 204, 0.28);
}

.login-submit:focus-visible {
    outline: none;
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.28), 0 8px 18px rgba(0, 105, 217, 0.22);
}

.login-submit:disabled {
    background: #dfe8f2;
    box-shadow: none;
    color: #8ea1b7;
    cursor: progress;
}

.login-spinner {
    display: none;
    width: 14px;
    height: 14px;
    border: 2px solid rgba(255, 255, 255, 0.4);
    border-top-color: currentColor;
    border-radius: 50%;
    animation: login-spin 0.7s linear infinite;
}

.login-submit:disabled .login-spinner {
    display: block;
}

@keyframes login-spin {
    to {
        transform: rotate(360deg);
    }
}

.login-note {
    margin: 16px 0 0;
    padding-top: 13px;
    border-top: 1px solid var(--ds-login-line);
    color: var(--ds-login-ink-4);
    font-size: 11px;
    line-height: 1.6;
}

/* --------------------------------------------------------------------------
   表单级错误
   -------------------------------------------------------------------------- */

.login-alert {
    margin-top: 18px;
    padding: 12px;
    border: 1px solid #f3c7c3;
    border-radius: var(--ds-login-radius);
    background: #fdf0ef;
    color: #8f2b22;
    font-size: 13px;
    line-height: 1.6;
}

.login-alert a {
    color: #8f2b22;
    text-decoration: underline;
    text-underline-offset: 2px;
}

.login-alert a:hover {
    color: #6f1f18;
}

/* --------------------------------------------------------------------------
   页脚
   -------------------------------------------------------------------------- */

.login-foot {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 24px;
    grid-column: 1 / -1;
    padding: 15px 0 0;
    border-top: 1px solid var(--ds-login-line);
    color: var(--ds-login-ink-4);
    font-size: 14px;
    line-height: 1.6;
}

/* --------------------------------------------------------------------------
   响应式
   -------------------------------------------------------------------------- */

@media (max-width: 1024px) {
    .login-stage {
        grid-template-columns: minmax(0, 1fr) 380px;
        column-gap: 44px;
    }

    .login-title {
        font-size: 50px;
    }
}

@media (max-width: 860px) {
    .login-stage {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto auto auto;
        padding: 0 20px 36px;
        min-height: 0;
    }

    .login-top {
        padding: 18px 0 14px;
    }

    .login-intro {
        padding: 34px 0 6px;
    }

    .login-title {
        font-size: 40px;
    }

    .login-lede {
        margin-top: 16px;
        font-size: 14px;
    }

    .login-panel-wrap {
        margin-top: 26px;
    }

    .login-panel {
        padding: 26px 22px 22px;
    }

    .login-foot {
        margin-top: 32px;
    }
}

@media (prefers-reduced-motion: reduce) {
    .login-intro > div,
    .login-panel-wrap {
        animation: none !important;
    }

    * {
        transition: none !important;
    }
}