:root {
    --color-bg: #f7f7f5;
    --color-surface: #ffffff;
    --color-text: #242424;
    --color-muted: #66625d;
    --color-line: #dedbd6;
    --color-line-strong: #c7c3bd;
    --color-primary: #2f4f4f;
    --color-primary-hover: #263f3f;
    --color-primary-active: #1f3434;
    --color-focus: #1a73e8;
    --shadow-panel: 0 18px 48px rgba(35, 32, 28, 0.08);
    --radius: 8px;
    --font-sans: "Helvetica Neue", "Hiragino Kaku Gothic ProN", "Yu Gothic", Arial, sans-serif;
    --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

* {
    box-sizing: border-box;
}

html {
    min-height: 100%;
    background: var(--color-bg);
}

body {
    min-height: 100vh;
    margin: 0;
    color: var(--color-text);
    background: linear-gradient(180deg, #ffffff 0%, var(--color-bg) 52%, #f1f1ef 100%);
    font-family: var(--font-sans);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

button,
input,
select,
textarea {
    font: inherit;
}

:focus-visible {
    outline: 2px solid var(--color-focus);
    outline-offset: 3px;
}

.app-shell {
    width: min(100%, 980px);
    margin: 0 auto;
    padding: 56px 24px 64px;
}

.app-header {
    margin-bottom: 28px;
    text-align: center;
}

h1 {
    margin: 0;
    font-size: clamp(2rem, 5vw, 3.2rem);
    font-weight: 650;
    line-height: 1.16;
    letter-spacing: 0;
}

.app-description {
    max-width: none;
    margin: 18px 0 0;
    color: var(--color-muted);
    font-size: 1rem;
    text-align: left;
}

.app-description span {
    display: block;
    margin-top: 8px;
}

.app-privacy {
    max-width: none;
    margin: 24px 0 0;
    color: #8b8782;
    font-size: 0.85rem;
    text-align: center;
}

.converter-panel {
    padding: 28px;
    border: 1px solid var(--color-line);
    border-radius: var(--radius);
    background: var(--color-surface);
    box-shadow: var(--shadow-panel);
}

.field {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.break-code-grid {
    display: grid;
    grid-template-columns: minmax(0, 280px) minmax(0, 280px);
    gap: 14px 18px;
    margin-bottom: 22px;
    align-items: end;
}

label {
    color: var(--color-text);
    font-size: 0.95rem;
    font-weight: 650;
}

input,
select,
textarea {
    width: 100%;
    border: 1px solid var(--color-line-strong);
    border-radius: var(--radius);
    color: var(--color-text);
    background: #fff;
    transition: border-color 0.16s ease, box-shadow 0.16s ease, background-color 0.16s ease;
}

input:hover,
select:hover,
textarea:hover {
    border-color: #aaa49c;
}

input:focus,
select:focus,
textarea:focus {
    border-color: var(--color-focus);
    box-shadow: 0 0 0 3px rgba(26, 115, 232, 0.14);
    outline: none;
}

input,
select {
    min-height: 48px;
    padding: 11px 13px;
}

select {
    cursor: pointer;
}

input {
    font-family: var(--font-mono);
}

.custom-code-field.is-hidden {
    display: none;
}

textarea {
    min-height: 230px;
    padding: 14px;
    resize: vertical;
    font-family: var(--font-mono);
    font-size: 0.96rem;
    line-height: 1.65;
}

textarea[readonly] {
    background: #fbfbfa;
}

.field-note {
    grid-column: 1 / -1;
    margin: 0;
    color: var(--color-muted);
    font-size: 0.86rem;
}

.text-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 22px;
}

.actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 24px;
}

.button {
    min-height: 46px;
    padding: 10px 18px;
    border: 1px solid var(--color-primary);
    border-radius: var(--radius);
    color: #fff;
    background: var(--color-primary);
    box-shadow: 0 3px 0 rgba(24, 42, 42, 0.28);
    cursor: pointer;
    font-weight: 650;
    line-height: 1.2;
    transition: transform 0.12s ease, border-color 0.12s ease, background-color 0.12s ease, box-shadow 0.12s ease;
}

.button:hover {
    border-color: var(--color-primary-hover);
    background: var(--color-primary-hover);
}

.button:active,
.button.is-pressed {
    border-color: var(--color-primary-active);
    background: var(--color-primary-active);
    box-shadow: 0 1px 0 rgba(24, 42, 42, 0.36);
    transform: translateY(2px);
}

.status-message {
    min-height: 1.7em;
    margin: 14px 0 0;
    color: var(--color-primary);
    font-size: 0.94rem;
}

@media (max-width: 720px) {
    .app-shell {
        padding: 36px 16px 44px;
    }

    .app-header {
        text-align: left;
    }

    .app-description {
        margin-left: 0;
        margin-right: 0;
    }

    .converter-panel {
        padding: 20px;
    }

    .break-code-grid {
        grid-template-columns: 1fr;
    }

    .text-grid {
        grid-template-columns: 1fr;
        gap: 18px;
    }

    textarea {
        min-height: 210px;
    }

    .actions {
        display: grid;
        grid-template-columns: 1fr;
    }

    .button {
        width: 100%;
        min-height: 50px;
    }
}