:root {
    color-scheme: light dark;
    --bg: #020617;
    --card: rgba(15, 23, 42, 0.9);
    --border: rgba(148, 163, 184, 0.2);
    --text: #f8fafc;
    --muted: rgba(248, 250, 252, 0.75);
    --accent: #38bdf8;
    --accent-strong: #22d3ee;
    --error: #f87171;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family:
        "Inter",
        "Noto Sans JP",
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        sans-serif;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: calc(env(safe-area-inset-top, 0px) + 48px) clamp(16px, 6vw, 48px)
        calc(env(safe-area-inset-bottom, 0px) + 48px);
    background: radial-gradient(circle at top, #0f172a, #010314 65%);
    color: var(--text);
    position: relative;
    overflow: hidden;
}

.sky {
    position: fixed;
    inset: 0;
    z-index: 0;
    overflow: hidden;
    pointer-events: none;
    background:
        radial-gradient(
            circle at 20% 15%,
            rgba(59, 130, 246, 0.08),
            transparent 35%
        ),
        radial-gradient(
            circle at 80% 20%,
            rgba(14, 165, 233, 0.08),
            transparent 30%
        );
}

.sky::after {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(
        circle at 50% 110%,
        rgba(2, 6, 23, 0.65),
        rgba(2, 6, 23, 0.95)
    );
}

.stars {
    position: absolute;
    inset: -30%;
    background-repeat: repeat;
    filter: drop-shadow(0 0 7px rgba(56, 189, 248, 0.4));
    opacity: 0.85;
}

.stars.layer-1 {
    background-image:
        radial-gradient(
            1px 1px at 20px 40px,
            rgba(248, 250, 252, 0.95),
            transparent 45%
        ),
        radial-gradient(
            1px 1px at 180px 120px,
            rgba(56, 189, 248, 0.85),
            transparent 55%
        ),
        radial-gradient(
            1.2px 1.2px at 280px 60px,
            rgba(255, 255, 255, 0.95),
            transparent 55%
        ),
        radial-gradient(
            0.95px 0.95px at 360px 220px,
            rgba(34, 211, 238, 0.85),
            transparent 55%
        ),
        radial-gradient(
            0.85px 0.85px at 440px 120px,
            rgba(248, 250, 252, 0.8),
            transparent 55%
        ),
        radial-gradient(
            1px 1px at 520px 260px,
            rgba(14, 165, 233, 0.85),
            transparent 55%
        ),
        radial-gradient(
            1px 1px at 600px 160px,
            rgba(255, 255, 255, 0.9),
            transparent 55%
        );
    background-size: 400px 400px;
    opacity: 0.72;
    animation: driftSlow 120s linear infinite;
}

.stars.layer-2 {
    background-image:
        radial-gradient(
            1px 1px at 50px 80px,
            rgba(255, 255, 255, 0.95),
            transparent 50%
        ),
        radial-gradient(
            1px 1px at 190px 30px,
            rgba(14, 165, 233, 0.95),
            transparent 60%
        ),
        radial-gradient(
            1px 1px at 320px 180px,
            rgba(236, 254, 255, 0.95),
            transparent 55%
        ),
        radial-gradient(
            1.1px 1.1px at 420px 280px,
            rgba(52, 211, 153, 0.9),
            transparent 60%
        ),
        radial-gradient(
            1px 1px at 520px 110px,
            rgba(255, 255, 255, 0.9),
            transparent 55%
        ),
        radial-gradient(
            1.1px 1.1px at 620px 230px,
            rgba(125, 211, 252, 0.85),
            transparent 60%
        ),
        radial-gradient(
            1px 1px at 700px 60px,
            rgba(255, 255, 255, 0.95),
            transparent 55%
        );
    background-size: 460px 460px;
    opacity: 0.78;
    animation: driftMedium 90s linear infinite;
}

.stars.layer-3 {
    background-image:
        radial-gradient(
            1.1px 1.1px at 30px 40px,
            rgba(255, 255, 255, 0.95),
            transparent 45%
        ),
        radial-gradient(
            1px 1px at 160px 140px,
            rgba(14, 165, 233, 0.95),
            transparent 50%
        ),
        radial-gradient(
            0.9px 0.9px at 280px 60px,
            rgba(236, 254, 255, 0.9),
            transparent 55%
        ),
        radial-gradient(
            0.85px 0.85px at 360px 220px,
            rgba(255, 255, 255, 0.95),
            transparent 55%
        ),
        radial-gradient(
            1.1px 1.1px at 440px 160px,
            rgba(52, 211, 153, 0.9),
            transparent 60%
        ),
        radial-gradient(
            1px 1px at 520px 280px,
            rgba(255, 255, 255, 0.95),
            transparent 55%
        ),
        radial-gradient(
            1px 1px at 620px 120px,
            rgba(14, 165, 233, 0.9),
            transparent 55%
        );
    background-size: 320px 320px;
    opacity: 0.9;
    animation:
        driftFast 70s linear infinite reverse,
        twinkle 6s ease-in-out infinite;
    mix-blend-mode: screen;
}

.panel {
    width: min(960px, 100%);
    padding: clamp(16px, 4vw, 28px);
    border-radius: 32px;
    background: rgba(15, 23, 42, 0.7);
    border: 1px solid rgba(148, 163, 184, 0.25);
    box-shadow: 0 25px 55px rgba(2, 6, 23, 0.65);
    backdrop-filter: blur(18px);
    position: relative;
    z-index: 1;
    animation: floatIn 600ms ease forwards;
}

.panel__grid {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.panel__content {
    display: none;
    padding: clamp(24px, 4vw, 36px);
    background: linear-gradient(
        145deg,
        rgba(15, 23, 42, 0.9),
        rgba(8, 47, 73, 0.7)
    );
    border-radius: 26px;
    border: 1px solid rgba(56, 189, 248, 0.15);
}

.panel__hero {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 32px;
}

.panel__eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 4px 10px;
    border-radius: 999px;
    border: 1px solid rgba(56, 189, 248, 0.4);
    background: rgba(56, 189, 248, 0.1);
    color: var(--accent-strong);
    font-size: 0.78rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    font-weight: 600;
    width: fit-content;
}

h1 {
    margin: 0 0 8px;
    font-size: clamp(1.8rem, 4vw, 2.4rem);
}

.lead {
    margin: 0 0 32px;
    color: var(--muted);
    line-height: 1.7;
    font-size: 1.02rem;
}

.panel__features {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 12px;
    color: rgba(248, 250, 252, 0.9);
}

.panel__features li {
    display: flex;
    gap: 10px;
    align-items: flex-start;
}

.panel__features li::before {
    content: "◆";
    color: var(--accent-strong);
    font-size: 0.85rem;
    margin-top: 4px;
}

.panel__form-wrapper {
    padding: clamp(24px, 4vw, 40px);
    background: linear-gradient(
        180deg,
        rgba(15, 23, 42, 0.95),
        rgba(15, 23, 42, 0.8)
    );
    border-radius: 26px;
    border: 1px solid rgba(148, 163, 184, 0.2);
    display: flex;
    flex-direction: column;
    gap: 16px;
    box-shadow: inset 0 0 12px rgba(8, 47, 73, 0.5);
}

.panel__form {
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.panel__support {
    margin-top: 20px;
    padding-top: 18px;
    border-top: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.panel__mobile-intro {
    display: none;
    flex-direction: column;
    gap: 8px;
    color: var(--muted);
}

.panel__mobile-intro h2 {
    margin: 0;
    font-size: 1.6rem;
    color: var(--text);
}

.panel__mobile-intro p {
    margin: 0;
    line-height: 1.6;
}

label {
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-weight: 600;
    letter-spacing: 0.02em;
}

input[type="text"],
input[type="password"] {
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 14px 16px;
    font-size: 1rem;
    background: rgba(15, 23, 42, 0.6);
    color: var(--text);
    transition:
        border 0.2s ease,
        background 0.2s ease;
}

input:focus {
    outline: none;
    border-color: rgba(56, 189, 248, 0.8);
    background: rgba(15, 23, 42, 0.8);
}

button[type="submit"] {
    border: none;
    border-radius: 16px;
    padding: 16px 18px;
    font-size: 1.05rem;
    font-weight: 600;
    cursor: pointer;
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    color: #0f172a;
    box-shadow: 0 15px 30px rgba(15, 23, 42, 0.55);
    width: 100%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition:
        transform 0.15s ease,
        box-shadow 0.15s ease;
}

button[type="submit"]:active {
    transform: translateY(1px);
    box-shadow: 0 8px 18px rgba(15, 23, 42, 0.55);
}

.error {
    margin-top: 16px;
    padding: 12px 14px;
    border-radius: 14px;
    border: 1px solid rgba(248, 113, 113, 0.4);
    background: rgba(248, 113, 113, 0.1);
    color: var(--error);
    font-weight: 600;
}

.note {
    margin-top: 20px;
    font-size: 0.95rem;
    color: var(--muted);
    line-height: 1.6;
}

.note code {
    display: inline-flex;
    border-radius: 8px;
    border: 1px solid rgba(148, 163, 184, 0.35);
    padding: 2px 8px;
    background: rgba(15, 23, 42, 0.7);
    font-size: 0.88rem;
    color: var(--text);
}

.hint,
.hint--mobile {
    margin: 0;
    font-size: 0.93rem;
    color: rgba(248, 250, 252, 0.85);
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.hint::before,
.hint--mobile::before {
    content: "";
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--accent-strong);
}

.hint--mobile {
    display: none;
    font-size: 0.9rem;
    color: rgba(248, 250, 252, 0.75);
}

@keyframes floatIn {
    from {
        opacity: 0;
        transform: translate3d(0, 30px, 0) scale(0.98);
    }

    to {
        opacity: 1;
        transform: translate3d(0, 0, 0) scale(1);
    }
}

@keyframes driftSlow {
    from {
        transform: translate3d(0, 0, 0);
    }

    to {
        transform: translate3d(240px, 180px, 0);
    }
}

@keyframes driftMedium {
    from {
        transform: translate3d(0, 0, 0) scale(1.05);
    }

    to {
        transform: translate3d(-200px, 140px, 0) scale(1.05);
    }
}

@keyframes driftFast {
    from {
        transform: translate3d(0, 0, 0) scale(1.1);
    }

    to {
        transform: translate3d(180px, -120px, 0) scale(1.1);
    }
}

@keyframes twinkle {
    0% {
        opacity: 0.6;
    }

    50% {
        opacity: 1;
    }

    100% {
        opacity: 0.6;
    }
}

@media (min-aspect-ratio: 4/3) and (min-width: 900px) {
    body {
        align-items: center;
        justify-content: center;
        padding: calc(env(safe-area-inset-top, 0px) + 60px)
            clamp(32px, 7vw, 80px) calc(env(safe-area-inset-bottom, 0px) + 60px);
    }

    .panel {
        padding: clamp(32px, 4vw, 48px);
    }

    .panel__grid {
        display: grid;
        grid-template-columns: 1.05fr 0.95fr;
        gap: clamp(24px, 3vw, 40px);
        align-items: stretch;
    }

    .panel__content {
        display: flex;
        flex-direction: column;
        justify-content: space-between;
    }

    .panel__support {
        margin-top: auto;
    }

    .panel__mobile-intro,
    .hint--mobile {
        display: none;
    }
}

@media (max-aspect-ratio: 3/4) {
    body {
        align-items: flex-start;
        justify-content: flex-start;
        padding-top: calc(env(safe-area-inset-top, 0px) + 32px);
        padding-bottom: calc(env(safe-area-inset-bottom, 0px) + 32px);
    }

    .panel {
        width: min(520px, 100%);
        padding: 0;
        border-radius: 0;
        background: transparent;
        border: none;
        box-shadow: none;
    }

    .panel__grid {
        gap: 16px;
    }

    .panel__content {
        display: none;
    }

    .panel__form-wrapper {
        border-radius: 24px;
    }

    .panel__mobile-intro {
        display: flex;
    }

    .hint--mobile {
        display: inline-flex;
    }
}

@media (max-aspect-ratio: 3/4) and (max-width: 480px) {
    body {
        padding-left: clamp(12px, 6vw, 24px);
        padding-right: clamp(12px, 6vw, 24px);
    }

    .panel__form-wrapper {
        padding: 24px 20px 28px;
    }

    h1 {
        font-size: clamp(1.6rem, 8vw, 2rem);
    }

    .panel__mobile-intro h2 {
        font-size: clamp(1.4rem, 7vw, 1.8rem);
    }

    input[type="text"],
    input[type="password"] {
        font-size: 0.95rem;
    }

    button[type="submit"] {
        font-size: 1rem;
        padding: 14px 16px;
    }

    .hint,
    .hint--mobile {
        font-size: 0.88rem;
    }
}