:root {
    color-scheme: dark;
}

/* =====================================================================
   순공야르 — standalone page design
   Mood: deep-focus study chamber. Quiet, dark, a single glowing ring.
   Motif: neon-teal progress ring (the timer), monospace digits,
   camera presence-detection states (공부 중 / 자리 비움 / 복귀).
   Teal focus glow + amber "away" accent on near-black.
   ===================================================================== */

.service-body--study {
    --st-bg: #05100e;
    --st-bg-2: #081a17;
    --st-surface: rgba(18, 36, 33, 0.72);
    --st-surface-2: rgba(12, 26, 24, 0.85);
    --st-teal: #2ff0c8;
    --st-teal-2: #19c7a6;
    --st-amber: #ff9a3d;
    --st-red: #ff5a52;
    --st-ink: #eafef9;
    --st-muted: #8aa6a0;
    --st-line: rgba(47, 240, 200, 0.14);
    color: var(--st-ink);
    background:
        radial-gradient(90% 60% at 78% -8%, rgba(47, 240, 200, 0.12) 0%, rgba(47, 240, 200, 0) 55%),
        radial-gradient(80% 55% at 0% 105%, rgba(25, 199, 166, 0.1) 0%, rgba(25, 199, 166, 0) 55%),
        linear-gradient(180deg, #05100e 0%, #04100d 60%, #050d0b 100%);
    background-attachment: fixed;
    min-height: 100vh;
    overflow-x: hidden;
    font-family: "Pretendard", "Space Grotesk", sans-serif;
    -webkit-font-smoothing: antialiased;
}

/* faint grid — like graph paper of a desk */
.st-grid {
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    background-image:
        linear-gradient(rgba(47, 240, 200, 0.045) 1px, transparent 1px),
        linear-gradient(90deg, rgba(47, 240, 200, 0.045) 1px, transparent 1px);
    background-size: 44px 44px;
    mask-image: radial-gradient(120% 80% at 50% 0%, #000 30%, transparent 78%);
    -webkit-mask-image: radial-gradient(120% 80% at 50% 0%, #000 30%, transparent 78%);
}

.service-body--study .service-main,
.service-body--study .st-topbar,
.service-body--study .service-footer {
    position: relative;
    z-index: 1;
}

/* ===== Top bar ===== */
.st-topbar {
    padding-top: clamp(1.4rem, 3vw, 2rem);
}

.st-topbar__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.st-topbar__brand {
    font-family: "Space Grotesk", sans-serif;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    font-size: 0.8rem;
    color: var(--st-muted);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px 8px 8px;
    background: rgba(18, 36, 33, 0.6);
    color: var(--st-ink);
    border-radius: 999px;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.92rem;
    border: 1px solid var(--st-line);
    backdrop-filter: blur(10px);
    transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.back-link__icon {
    width: 30px;
    height: 30px;
    display: grid;
    place-items: center;
    border-radius: 50%;
    background: linear-gradient(150deg, var(--st-teal), var(--st-teal-2));
    color: #04100d;
    font-size: 1rem;
    font-weight: 700;
}

.back-link:hover,
.back-link:focus-visible {
    transform: translateY(-2px);
    border-color: rgba(47, 240, 200, 0.5);
    box-shadow: 0 14px 34px -22px rgba(47, 240, 200, 0.8);
}

/* ===== Buttons ===== */
.st-btn {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    padding: 14px 24px;
    border-radius: 14px;
    font-weight: 700;
    font-size: 1rem;
    text-decoration: none;
    transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}

.st-btn--primary {
    background: linear-gradient(135deg, var(--st-teal), var(--st-teal-2));
    color: #04130f;
    box-shadow: 0 18px 40px -18px rgba(47, 240, 200, 0.7);
}

.st-btn--primary:hover,
.st-btn--primary:focus-visible {
    transform: translateY(-2px);
    box-shadow: 0 24px 50px -18px rgba(47, 240, 200, 0.85);
}

.st-btn--ghost {
    background: rgba(18, 36, 33, 0.5);
    color: var(--st-ink);
    border: 1px solid var(--st-line);
}

.st-btn--ghost:hover,
.st-btn--ghost:focus-visible {
    transform: translateY(-2px);
    border-color: rgba(47, 240, 200, 0.5);
    background: rgba(24, 48, 44, 0.7);
}

/* ===== Hero ===== */
.st-hero {
    display: grid;
    grid-template-columns: 1.05fr 0.95fr;
    gap: clamp(2rem, 5vw, 4.5rem);
    align-items: center;
    padding-top: clamp(2.5rem, 6vw, 5rem);
    padding-bottom: clamp(2.5rem, 6vw, 4.5rem);
}

.st-kicker {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    padding: 7px 15px;
    border-radius: 999px;
    background: rgba(47, 240, 200, 0.08);
    border: 1px solid var(--st-line);
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.01em;
    color: var(--st-teal);
}

.st-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--st-teal);
    box-shadow: 0 0 0 0 rgba(47, 240, 200, 0.55);
    animation: st-pulse 2.2s ease-out infinite;
}

.st-hero__title {
    font-family: "Space Grotesk", "Pretendard", sans-serif;
    font-weight: 700;
    font-size: clamp(2.5rem, 6vw, 4.1rem);
    line-height: 1.06;
    letter-spacing: -0.02em;
    margin: 1.1rem 0 0;
}

.st-hero__title span {
    background: linear-gradient(110deg, var(--st-teal) 0%, #7df9e0 50%, var(--st-teal-2) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.st-hero__lead {
    margin: 1.3rem 0 0;
    max-width: 30rem;
    color: var(--st-muted);
    font-size: 1.08rem;
    line-height: 1.7;
}

.st-hero__actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.85rem;
    margin-top: 2rem;
}

.st-stats {
    display: flex;
    flex-wrap: wrap;
    gap: 1.6rem;
    margin: 2.4rem 0 0;
    padding: 0;
    list-style: none;
}

.st-stats li {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.st-stats strong {
    font-family: "Space Grotesk", sans-serif;
    font-size: 1.25rem;
    color: var(--st-ink);
}

.st-stats span {
    font-size: 0.84rem;
    color: var(--st-muted);
}

/* ===== Hero visual — the glowing focus ring ===== */
.st-hero__visual {
    position: relative;
    display: grid;
    place-items: center;
}

.st-ring-card {
    position: relative;
    width: min(100%, 380px);
    padding: 22px 22px 24px;
    border-radius: 30px;
    background: var(--st-surface-2);
    border: 1px solid var(--st-line);
    backdrop-filter: blur(14px);
    box-shadow: 0 40px 90px -50px rgba(0, 0, 0, 0.9), inset 0 1px 0 rgba(255, 255, 255, 0.04);
}

.st-ring-card__top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    margin-bottom: 20px;
}

.st-chip {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 6px 12px;
    border-radius: 999px;
    font-size: 0.78rem;
    font-weight: 700;
}

.st-chip--live {
    background: rgba(47, 240, 200, 0.12);
    color: var(--st-teal);
    border: 1px solid rgba(47, 240, 200, 0.3);
}

.st-chip--cam {
    background: rgba(255, 255, 255, 0.05);
    color: var(--st-muted);
    border: 1px solid rgba(255, 255, 255, 0.08);
}

.st-pulse {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--st-teal);
    box-shadow: 0 0 0 0 rgba(47, 240, 200, 0.6);
    animation: st-pulse 1.8s ease-out infinite;
}

.st-ring {
    position: relative;
    width: min(78%, 260px);
    aspect-ratio: 1;
    margin: 0 auto;
    border-radius: 50%;
    display: grid;
    place-items: center;
    /* 70% progress arc */
    background:
        radial-gradient(closest-side, var(--st-surface-2) 0 70%, transparent 71% 100%),
        conic-gradient(var(--st-teal) 0% 70%, rgba(47, 240, 200, 0.12) 70% 100%);
    filter: drop-shadow(0 0 18px rgba(47, 240, 200, 0.35));
}

.st-ring::before {
    content: "";
    position: absolute;
    inset: -7px;
    border-radius: 50%;
    background: conic-gradient(rgba(47, 240, 200, 0.55) 0% 70%, transparent 70% 100%);
    filter: blur(11px);
    opacity: 0.6;
    z-index: -1;
}

.st-ring__core {
    display: grid;
    place-items: center;
    gap: 5px;
    text-align: center;
}

.st-ring__label {
    font-size: 0.78rem;
    color: var(--st-muted);
}

.st-ring__time {
    font-family: "JetBrains Mono", monospace;
    font-weight: 700;
    font-size: clamp(1.5rem, 5vw, 1.9rem);
    letter-spacing: 0.02em;
    color: var(--st-ink);
    text-shadow: 0 0 22px rgba(47, 240, 200, 0.45);
}

.st-ring__goal {
    font-size: 0.76rem;
    color: var(--st-muted);
}

.st-start {
    display: block;
    width: 100%;
    margin-top: 22px;
    padding: 13px;
    border-radius: 14px;
    border: 1px solid rgba(47, 240, 200, 0.4);
    background: rgba(47, 240, 200, 0.1);
    color: var(--st-teal);
    font-weight: 700;
    font-size: 0.98rem;
    font-family: inherit;
    cursor: default;
}

.st-bubble {
    position: absolute;
    left: -10px;
    bottom: 26px;
    padding: 9px 15px;
    border-radius: 14px;
    background: linear-gradient(135deg, var(--st-teal), var(--st-teal-2));
    color: #04130f;
    font-size: 0.82rem;
    font-weight: 700;
    box-shadow: 0 18px 40px -18px rgba(47, 240, 200, 0.8);
    animation: st-bob 4s ease-in-out infinite;
}

/* ===== Section heads ===== */
.st-section__head {
    text-align: center;
    max-width: 40rem;
    margin: 0 auto clamp(2rem, 4vw, 3rem);
}

.st-section__eyebrow {
    font-family: "Space Grotesk", sans-serif;
    text-transform: uppercase;
    letter-spacing: 0.22em;
    font-size: 0.74rem;
    font-weight: 600;
    color: var(--st-teal);
}

.st-section__title {
    font-family: "Space Grotesk", "Pretendard", sans-serif;
    font-weight: 700;
    font-size: clamp(1.7rem, 4vw, 2.6rem);
    line-height: 1.16;
    letter-spacing: -0.01em;
    margin: 0.7rem 0 0;
}

.st-section__title span {
    color: var(--st-teal);
}

.st-section__sub {
    margin: 0.9rem 0 0;
    color: var(--st-muted);
    font-size: 1rem;
    line-height: 1.65;
}

/* ===== Presence states ===== */
.st-states {
    padding-top: clamp(2rem, 5vw, 3.5rem);
}

.st-state-row {
    display: flex;
    align-items: stretch;
    justify-content: center;
    gap: 0.4rem;
    flex-wrap: wrap;
}

.st-state {
    flex: 1 1 220px;
    max-width: 300px;
    padding: 26px 22px;
    border-radius: 22px;
    background: var(--st-surface);
    border: 1px solid var(--st-line);
    backdrop-filter: blur(10px);
}

.st-state__tag {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 5px 13px;
    border-radius: 999px;
    font-size: 0.8rem;
    font-weight: 700;
}

.st-state--on .st-state__tag {
    background: rgba(47, 240, 200, 0.14);
    color: var(--st-teal);
    border: 1px solid rgba(47, 240, 200, 0.32);
}

.st-state--away .st-state__tag {
    background: rgba(255, 154, 61, 0.16);
    color: var(--st-amber);
    border: 1px solid rgba(255, 154, 61, 0.36);
}

.st-state--back .st-state__tag {
    background: rgba(125, 249, 224, 0.12);
    color: #7df9e0;
    border: 1px solid rgba(125, 249, 224, 0.3);
}

.st-state__time {
    display: block;
    margin: 16px 0 10px;
    font-family: "JetBrains Mono", monospace;
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--st-ink);
}

.st-state--away .st-state__time {
    color: var(--st-amber);
}

.st-state p {
    margin: 0;
    color: var(--st-muted);
    font-size: 0.92rem;
    line-height: 1.6;
}

.st-state__arrow {
    align-self: center;
    color: var(--st-muted);
    font-size: 1.4rem;
}

/* ===== How it works ===== */
.st-flow {
    padding-top: clamp(3rem, 7vw, 5.5rem);
}

.st-steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.2rem;
    margin: 0;
    padding: 0;
    list-style: none;
    counter-reset: none;
}

.st-step {
    position: relative;
    padding: 30px 24px 26px;
    border-radius: 22px;
    background: var(--st-surface);
    border: 1px solid var(--st-line);
    backdrop-filter: blur(10px);
    overflow: hidden;
}

.st-step__num {
    font-family: "JetBrains Mono", monospace;
    font-weight: 700;
    font-size: 0.86rem;
    color: var(--st-teal);
    letter-spacing: 0.08em;
}

.st-step__icon {
    display: grid;
    place-items: center;
    width: 52px;
    height: 52px;
    margin: 14px 0 16px;
    border-radius: 15px;
    background: rgba(47, 240, 200, 0.1);
    border: 1px solid rgba(47, 240, 200, 0.22);
    font-size: 1.4rem;
    color: var(--st-teal);
}

.st-step h3 {
    margin: 0 0 8px;
    font-size: 1.18rem;
    font-weight: 700;
}

.st-step p {
    margin: 0;
    color: var(--st-muted);
    font-size: 0.94rem;
    line-height: 1.62;
}

/* ===== Features ===== */
.st-features {
    padding-top: clamp(3rem, 7vw, 5.5rem);
}

/* row-list layout — distinct from the numbered step cards */
.st-feat-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.9rem 1.4rem;
}

.st-feat-row {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 18px 22px 18px 18px;
    border-radius: 16px;
    background: linear-gradient(90deg, rgba(47, 240, 200, 0.06), rgba(47, 240, 200, 0) 60%);
    border-left: 2px solid rgba(47, 240, 200, 0.4);
    transition: border-color 0.25s ease, transform 0.25s ease, background 0.25s ease;
}

.st-feat-row:hover {
    transform: translateX(4px);
    border-left-color: var(--st-teal);
    background: linear-gradient(90deg, rgba(47, 240, 200, 0.12), rgba(47, 240, 200, 0) 60%);
}

.st-feat-row__icon {
    flex: 0 0 auto;
    display: grid;
    place-items: center;
    width: 46px;
    height: 46px;
    border-radius: 50%;
    background: rgba(47, 240, 200, 0.1);
    font-size: 1.3rem;
}

.st-feat-row__text {
    min-width: 0;
}

.st-feat-row h3 {
    margin: 0 0 4px;
    font-size: 1.02rem;
    font-weight: 700;
}

.st-feat-row p {
    margin: 0;
    color: var(--st-muted);
    font-size: 0.88rem;
    line-height: 1.55;
}

/* ===== Screenshots ===== */
.st-shots {
    padding-top: clamp(3rem, 7vw, 5.5rem);
}

.st-shot-row {
    display: flex;
    justify-content: center;
    gap: clamp(1.2rem, 4vw, 2.6rem);
    flex-wrap: wrap;
}

.st-phone {
    margin: 0;
    width: min(46%, 280px);
    border-radius: 32px;
    overflow: hidden;
    border: 1px solid var(--st-line);
    box-shadow: 0 40px 90px -50px rgba(0, 0, 0, 0.9);
    transition: transform 0.3s ease;
}

.st-phone:first-child {
    transform: rotate(-3deg);
}

.st-phone:last-child {
    transform: rotate(3deg);
}

.st-phone:hover {
    transform: rotate(0) translateY(-6px);
}

.st-phone img {
    display: block;
    width: 100%;
    height: auto;
}

/* ===== CTA ===== */
.st-cta {
    padding-top: clamp(3.5rem, 8vw, 6rem);
    padding-bottom: clamp(3.5rem, 8vw, 6rem);
}

.st-cta__card {
    position: relative;
    max-width: 760px;
    margin: 0 auto;
    padding: clamp(2.4rem, 5vw, 3.6rem);
    border-radius: 30px;
    text-align: center;
    background:
        radial-gradient(120% 100% at 50% 0%, rgba(47, 240, 200, 0.14) 0%, rgba(47, 240, 200, 0) 60%),
        var(--st-surface-2);
    border: 1px solid rgba(47, 240, 200, 0.26);
    overflow: hidden;
}

.st-cta__glow {
    position: absolute;
    top: -40%;
    left: 50%;
    transform: translateX(-50%);
    width: 320px;
    height: 320px;
    border-radius: 50%;
    background: radial-gradient(closest-side, rgba(47, 240, 200, 0.35), transparent 70%);
    filter: blur(20px);
    pointer-events: none;
}

.st-cta__card h2 {
    position: relative;
    font-family: "Space Grotesk", "Pretendard", sans-serif;
    font-weight: 700;
    font-size: clamp(1.8rem, 4.5vw, 2.7rem);
    line-height: 1.18;
    margin: 0;
}

.st-cta__card p {
    position: relative;
    max-width: 32rem;
    margin: 1.1rem auto 0;
    color: var(--st-muted);
    font-size: 1.04rem;
    line-height: 1.7;
}

.st-cta__actions {
    position: relative;
    display: flex;
    flex-wrap: wrap;
    gap: 0.85rem;
    justify-content: center;
    margin-top: 2rem;
}

/* ===== Footer ===== */
.service-footer {
    padding: 2.4rem 0 3rem;
    text-align: center;
    border-top: 1px solid var(--st-line);
}

.service-footer p {
    margin: 0;
    color: var(--st-muted);
    font-size: 0.88rem;
}

/* ===== Animations ===== */
@keyframes st-pulse {
    0% { box-shadow: 0 0 0 0 rgba(47, 240, 200, 0.55); }
    70% { box-shadow: 0 0 0 12px rgba(47, 240, 200, 0); }
    100% { box-shadow: 0 0 0 0 rgba(47, 240, 200, 0); }
}

@keyframes st-bob {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

[data-animate] {
    opacity: 0;
    transform: translateY(26px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

[data-animate].is-visible {
    opacity: 1;
    transform: none;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
    .st-hero {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .st-hero__lead {
        margin-left: auto;
        margin-right: auto;
    }

    .st-hero__actions,
    .st-stats {
        justify-content: center;
    }

    .st-hero__visual {
        order: -1;
    }

    .st-feat-list {
        grid-template-columns: repeat(2, 1fr);
    }

    .st-state__arrow {
        transform: rotate(90deg);
    }
}

@media (max-width: 620px) {
    .st-steps {
        grid-template-columns: 1fr;
    }

    .st-feat-list {
        grid-template-columns: 1fr;
    }

    .st-state {
        max-width: none;
    }

    .st-stats {
        gap: 1.1rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    .st-dot,
    .st-pulse,
    .st-bubble {
        animation: none;
    }

    [data-animate] {
        opacity: 1;
        transform: none;
        transition: none;
    }
}