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

:root {
    --bg: #ffffff;
    --surface: #ffffff;
    --text: #000000;
    --text-soft: #2f2f2f;
    --text-muted: #4a4a4a;
    --border: #d8d8d8;
    --capsule-bg: #ffffff;
    --toggle-hover: #eeeeee;
}

html[data-theme='dark'] {
    --bg: #000000;
    --surface: #1a1d21;
    --text: #f4f6f8;
    --text-soft: #d5dae0;
    --text-muted: #b2bac4;
    --border: #35404b;
    --capsule-bg: #20252a;
    --toggle-hover: #2a2a2a;
}

body {
    font-family: 'Geist', sans-serif;
    background: var(--bg);
    color: var(--text);
    padding: 1.1rem 1.1rem 2rem;
    line-height: 1.5;
    transition: background-color 200ms ease, color 200ms ease;
}

.page-wrap {
    width: 100%;
    max-width: 820px;
    margin: 0 auto;
}

.page-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.8rem;
}

.back-home {
    display: inline-flex;
    align-items: center;
    gap: 0.42rem;
    text-decoration: none;
    color: var(--text-soft);
    font-size: 0.88rem;
    line-height: 1;
    margin-top: 0.25rem;
    margin-bottom: 1rem;
    transition: color 180ms ease, transform 180ms ease;
}

.back-home-arrow {
    display: inline-block;
    transition: transform 180ms ease;
}

.back-home-arrow svg {
    width: 0.98rem;
    height: 0.98rem;
    stroke: currentColor;
    stroke-width: 2;
    fill: none;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.back-home:hover {
    color: var(--text);
    transform: translateX(-2px);
}

.back-home:hover .back-home-arrow {
    transform: translateX(-3px);
}

.stack-title {
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--text);
}

.stack-subtitle {
    margin-top: 0.28rem;
    font-size: 0.86rem;
    color: var(--text-muted);
    line-height: 1.6;
}

.tech-stack-groups {
    margin-top: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.95rem;
}

.tech-group h3 {
    margin: 0;
    font-size: 1.02rem;
    font-weight: 700;
    color: var(--text);
    line-height: 1.45;
}

.tech-capsules {
    margin-top: 0.3rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.42rem;
}

.tech-capsule {
    display: inline-flex;
    align-items: center;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: var(--capsule-bg);
    color: var(--text);
    font-size: 0.84rem;
    line-height: 1;
    padding: 0.35rem 0.58rem;
}

.theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: none;
    background: var(--surface);
    color: var(--text);
    border-radius: 50%;
    width: 2.1rem;
    height: 2.1rem;
    padding: 0;
    cursor: pointer;
    transition: background-color 0.5s ease, transform 0.5s ease;
}

.theme-toggle:hover {
    background: var(--toggle-hover);
    transform: translateY(-1px);
}

.theme-toggle-icon {
    width: 1rem;
    height: 1rem;
    display: inline-block;
    position: relative;
}

.theme-toggle-icon svg {
    width: 100%;
    height: 100%;
    fill: none;
    stroke: currentColor;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
    position: absolute;
    top: 0;
    left: 0;
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.theme-icon-sun {
    opacity: 1;
    transform: rotate(0deg);
}

.theme-icon-moon {
    opacity: 0;
    transform: rotate(-90deg);
}

html[data-theme='dark'] .theme-icon-sun {
    opacity: 0;
    transform: rotate(90deg);
}

html[data-theme='dark'] .theme-icon-moon {
    opacity: 1;
    transform: rotate(0deg);
}

@media (max-width: 820px) {
    body {
        padding: 1rem 0.95rem 1.4rem;
    }

    .page-wrap {
        max-width: 100%;
    }

    .stack-title {
        font-size: 1.2rem;
    }

    .stack-subtitle {
        font-size: 0.9rem;
        line-height: 1.7;
    }
}

@media (max-width: 700px) {
    .back-home {
        font-size: 0.83rem;
    }

    .theme-toggle {
        width: 2rem;
        height: 2rem;
    }

    .tech-stack-groups {
        gap: 0.8rem;
    }

    .tech-group h3 {
        font-size: 0.96rem;
    }

    .tech-capsules {
        gap: 0.38rem;
    }

    .tech-capsule {
        font-size: 0.8rem;
        padding: 0.36rem 0.54rem;
    }
}

@media (max-width: 520px) {
    body {
        padding: 0.9rem 0.78rem 1.2rem;
    }

    .page-head {
        gap: 0.55rem;
    }

    .stack-title {
        font-size: 1.08rem;
    }

    .stack-subtitle {
        font-size: 0.84rem;
        line-height: 1.6;
    }
}