/* =========================================================================
   Skiller Calculator Hub — Styles v1.1.2
   + Выражение крупное, результат мелкий (до =)
   + После = — выражение скрыто, результат крупный
   + Многослойная тень
   ========================================================================= */

.skh-wrap {
    --skh-navy-900:    #071634;
    --skh-navy-800:    #0a1f44;
    --skh-navy-700:    #0f2a5a;
    --skh-navy-600:    #16386f;
    --skh-navy-500:    #1e4784;
    --skh-orange:      #ff7a1a;
    --skh-orange-hi:   #ff9440;
    --skh-orange-lo:   #e0650a;
    --skh-orange-glow: rgba(255, 122, 26, 0.35);
    --skh-text:        #ffffff;
    --skh-text-soft:   #93a9ce;
    --skh-border:      rgba(255, 255, 255, 0.08);
    --skh-border-hi:   rgba(255, 255, 255, 0.16);

    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 48px 16px;
    box-sizing: border-box;
    width: 100%;
}

.skh-wrap *,
.skh-wrap *::before,
.skh-wrap *::after {
    box-sizing: border-box;
}

/* =========================================================================
   CARD — с многослойной тенью
   ========================================================================= */

.skh-card {
    width: 100%;
    max-width: 660px;
    margin: 0 auto;
    padding: 22px 20px 16px;
    background:
        radial-gradient(circle at 20% 0%, rgba(255, 122, 26, 0.08), transparent 55%),
        radial-gradient(circle at 100% 100%, rgba(30, 71, 132, 0.35), transparent 60%),
        linear-gradient(160deg, var(--skh-navy-900) 0%, var(--skh-navy-800) 45%, var(--skh-navy-700) 100%);
    border: 1px solid var(--skh-border);
    border-radius: 22px;

    /* Многослойная тень: ближняя + средняя + дальняя + оранжевое свечение */
    box-shadow:
        0 1px 0 rgba(255, 255, 255, 0.06) inset,
        0 2px 4px rgba(3, 12, 34, 0.25),
        0 12px 28px rgba(3, 12, 34, 0.35),
        0 32px 64px rgba(3, 12, 34, 0.45),
        0 0 0 1px rgba(255, 122, 26, 0.06),
        0 20px 80px -20px rgba(255, 122, 26, 0.22);

    color: var(--skh-text);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
    position: relative;
    overflow: hidden;
}

.skh-card::before {
    content: "";
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--skh-orange) 0%, var(--skh-orange-hi) 50%, var(--skh-orange) 100%);
    opacity: 0.9;
}

/* =========================================================================
   TITLE
   ========================================================================= */

.skh-title {
    margin: 0 0 14px;
    text-align: center;
    font-size: 21px;
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.01em;
    background: linear-gradient(135deg, var(--skh-orange-hi) 0%, var(--skh-orange) 60%, var(--skh-orange-lo) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: var(--skh-orange);
    text-shadow: 0 0 30px rgba(255, 122, 26, 0.25);
    padding: 0 4px;
}

/* =========================================================================
   DISPLAY
   ========================================================================= */

.skh-display {
    position: relative;
    padding: 26px 18px 14px;
    margin-bottom: 14px;
    background: rgba(3, 12, 34, 0.6);
    border: 1px solid var(--skh-border);
    border-radius: 12px;
    min-height: 110px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    text-align: right;
    overflow: hidden;
    box-shadow:
        0 1px 0 rgba(255, 255, 255, 0.03) inset,
        0 2px 8px rgba(3, 12, 34, 0.3) inset;
    transition: border-color .2s ease;
}

.skh-display::after {
    content: "";
    position: absolute;
    inset: 0;
    pointer-events: none;
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.02), transparent 40%);
    border-radius: inherit;
}

/* =========================================================================
   INDICATORS
   ========================================================================= */

.skh-indicators {
    position: absolute;
    top: 9px;
    left: 11px;
    display: flex;
    gap: 5px;
    align-items: center;
    pointer-events: none;
    z-index: 2;
}

.skh-indicator {
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    padding: 2px 6px;
    border-radius: 4px;
    background: rgba(255, 255, 255, 0.06);
    color: var(--skh-text-soft);
    border: 1px solid var(--skh-border);
    line-height: 1;
}

.skh-indicator--mode {
    color: var(--skh-orange);
    border-color: rgba(255, 122, 26, 0.3);
    background: rgba(255, 122, 26, 0.08);
}

.skh-indicator--mem {
    color: #7ee0a0;
    border-color: rgba(126, 224, 160, 0.3);
    background: rgba(126, 224, 160, 0.08);
}
.skh-indicator--mem[hidden] { display: none; }

/* =========================================================================
   EXPR + RESULT — ДО нажатия "="
   Выражение КРУПНОЕ, результат-preview МЕЛКИЙ.
   ========================================================================= */

.skh-expr {
    font-size: 26px;
    font-weight: 600;
    color: var(--skh-text);
    line-height: 1.2;
    min-height: 32px;
    max-height: 3.6em;
    overflow-y: auto;
    overflow-x: hidden;
    word-break: break-all;
    overflow-wrap: anywhere;
    font-variant-numeric: tabular-nums;
    letter-spacing: -0.01em;
    scrollbar-width: thin;
    scrollbar-color: rgba(255,122,26,0.3) transparent;
    transition: opacity .18s ease, transform .18s ease;
}
.skh-expr::-webkit-scrollbar { width: 4px; }
.skh-expr::-webkit-scrollbar-thumb {
    background: rgba(255,122,26,0.35);
    border-radius: 2px;
}

.skh-result {
    font-size: 15px;
    font-weight: 500;
    color: var(--skh-text-soft);
    line-height: 1.3;
    margin-top: 4px;
    word-break: break-all;
    overflow-wrap: anywhere;
    font-variant-numeric: tabular-nums;
    opacity: 0.85;
    transition: all .22s ease;
}

.skh-result.is-error {
    color: #ff5f5f;
    font-size: 15px;
    font-weight: 600;
    opacity: 1;
}

/* =========================================================================
   RESULT STATE (после нажатия "=")
   Выражение СКРЫТО, результат КРУПНЫЙ.
   ========================================================================= */

.skh-display.is-result {
    border-color: rgba(255, 122, 26, 0.22);
}

.skh-display.is-result .skh-expr {
    opacity: 0;
    transform: translateY(-6px);
    pointer-events: none;
    min-height: 0;
    max-height: 0;
    margin: 0;
    padding: 0;
}

.skh-display.is-result .skh-result {
    font-size: 42px;
    font-weight: 700;
    color: var(--skh-orange);
    text-shadow: 0 0 26px rgba(255, 122, 26, 0.35);
    letter-spacing: -0.02em;
    opacity: 1;
    margin-top: 0;
}

.skh-display.is-result .skh-result.is-error {
    font-size: 20px;
    color: #ff5f5f;
    text-shadow: 0 0 24px rgba(255, 95, 95, 0.3);
}

/* =========================================================================
   BUTTONS
   ========================================================================= */

.skh-buttons {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 8px;
}

.skh-btn {
    appearance: none;
    -webkit-appearance: none;
    border: 1px solid var(--skh-border);
    background: linear-gradient(180deg, rgba(30, 71, 132, 0.7) 0%, rgba(15, 42, 90, 0.7) 100%);
    color: var(--skh-text);
    font-family: inherit;
    font-size: 16px;
    font-weight: 600;
    line-height: 1;
    height: 50px;
    padding: 0;
    border-radius: 10px;
    cursor: pointer;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
    transition:
        background-color .12s ease,
        border-color .12s ease,
        color .12s ease,
        transform .06s ease,
        box-shadow .12s ease;
    box-shadow:
        0 1px 0 rgba(255, 255, 255, 0.06) inset,
        0 2px 4px rgba(3, 12, 34, 0.35);
    outline: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
    white-space: nowrap;
}

.skh-btn:hover {
    border-color: var(--skh-border-hi);
    background: linear-gradient(180deg, rgba(30, 71, 132, 0.95) 0%, rgba(15, 42, 90, 0.95) 100%);
}

.skh-btn:active,
.skh-btn.is-pressed {
    transform: translateY(1px);
    box-shadow:
        0 1px 0 rgba(255, 255, 255, 0.04) inset,
        0 1px 2px rgba(3, 12, 34, 0.4);
}

.skh-btn:focus-visible {
    box-shadow: 0 0 0 3px var(--skh-orange-glow);
    border-color: var(--skh-orange);
}

/* Function buttons */
.skh-btn--fn {
    font-size: 13px;
    font-weight: 600;
    color: #ffd9b0;
    background: linear-gradient(180deg, rgba(255, 122, 26, 0.12) 0%, rgba(255, 122, 26, 0.05) 100%);
    border-color: rgba(255, 122, 26, 0.28);
}
.skh-btn--fn:hover {
    color: #fff;
    background: linear-gradient(180deg, rgba(255, 122, 26, 0.22) 0%, rgba(255, 122, 26, 0.1) 100%);
    border-color: rgba(255, 122, 26, 0.55);
}

/* Memory */
.skh-btn--mem {
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.02em;
    color: #7ee0a0;
    background: linear-gradient(180deg, rgba(63, 185, 80, 0.12) 0%, rgba(63, 185, 80, 0.04) 100%);
    border-color: rgba(126, 224, 160, 0.28);
}
.skh-btn--mem:hover {
    color: #fff;
    background: linear-gradient(180deg, rgba(63, 185, 80, 0.25) 0%, rgba(63, 185, 80, 0.12) 100%);
    border-color: #7ee0a0;
}

/* Mode */
.skh-btn--mode {
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 0.05em;
    color: #fff;
    background: linear-gradient(180deg, rgba(90, 130, 220, 0.28) 0%, rgba(60, 90, 180, 0.18) 100%);
    border-color: rgba(120, 160, 240, 0.4);
}
.skh-btn--mode:hover {
    background: linear-gradient(180deg, rgba(120, 160, 240, 0.4) 0%, rgba(90, 130, 220, 0.25) 100%);
    border-color: rgba(150, 190, 255, 0.6);
}

/* Constants */
.skh-btn--const {
    font-size: 16px;
    font-weight: 700;
    color: #cbb6ff;
    background: linear-gradient(180deg, rgba(160, 120, 240, 0.16) 0%, rgba(120, 90, 200, 0.08) 100%);
    border-color: rgba(180, 150, 250, 0.32);
}
.skh-btn--const:hover {
    color: #fff;
    background: linear-gradient(180deg, rgba(160, 120, 240, 0.3) 0%, rgba(120, 90, 200, 0.16) 100%);
    border-color: rgba(200, 180, 255, 0.6);
}

/* Action */
.skh-btn--action {
    color: #ffb27a;
    background: linear-gradient(180deg, rgba(224, 101, 10, 0.18) 0%, rgba(224, 101, 10, 0.08) 100%);
    border-color: rgba(255, 122, 26, 0.28);
    font-size: 15px;
}
.skh-btn--action:hover {
    color: #fff;
    background: linear-gradient(180deg, rgba(224, 101, 10, 0.3) 0%, rgba(224, 101, 10, 0.15) 100%);
    border-color: var(--skh-orange);
}

/* Operator */
.skh-btn--op {
    color: var(--skh-orange);
    font-size: 19px;
    font-weight: 700;
    background: linear-gradient(180deg, rgba(255, 122, 26, 0.08) 0%, rgba(15, 42, 90, 0.7) 100%);
    border-color: rgba(255, 122, 26, 0.3);
}
.skh-btn--op:hover {
    color: #fff;
    background: linear-gradient(180deg, rgba(255, 122, 26, 0.3) 0%, rgba(255, 122, 26, 0.15) 100%);
    border-color: var(--skh-orange);
    box-shadow: 0 4px 14px var(--skh-orange-glow);
}

/* Equals */
.skh-btn--eq {
    color: #fff;
    font-size: 20px;
    font-weight: 700;
    background: linear-gradient(180deg, var(--skh-orange-hi) 0%, var(--skh-orange) 55%, var(--skh-orange-lo) 100%);
    border-color: var(--skh-orange);
    box-shadow:
        0 1px 0 rgba(255, 255, 255, 0.28) inset,
        0 6px 18px var(--skh-orange-glow);
    letter-spacing: 0.05em;
}
.skh-btn--eq:hover {
    filter: brightness(1.06);
    box-shadow:
        0 1px 0 rgba(255, 255, 255, 0.32) inset,
        0 8px 22px var(--skh-orange-glow);
}
.skh-btn--eq:active {
    transform: translateY(1px);
    box-shadow:
        0 1px 0 rgba(255, 255, 255, 0.22) inset,
        0 2px 8px var(--skh-orange-glow);
}

/* =========================================================================
   FOOTER
   ========================================================================= */

.skh-footer {
    margin-top: 12px;
    padding-top: 10px;
    border-top: 1px solid var(--skh-border);
    text-align: center;
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: rgba(147, 169, 206, 0.55);
}
.skh-footer span {
    color: var(--skh-orange);
    opacity: 0.7;
    margin: 0 4px;
}

/* =========================================================================
   RESPONSIVE
   ========================================================================= */

@media (max-width: 720px) {
    .skh-wrap {
        padding: 28px 12px;
    }
    .skh-card {
        padding: 20px 16px 14px;
        border-radius: 18px;
    }
    .skh-title {
        font-size: 19px;
    }
    .skh-btn {
        height: 46px;
        font-size: 15px;
        border-radius: 9px;
    }
    .skh-btn--fn,
    .skh-btn--mem {
        font-size: 11px;
    }
    .skh-btn--mode { font-size: 11px; }
    .skh-btn--const { font-size: 14px; }
    .skh-btn--op { font-size: 17px; }
    .skh-btn--action { font-size: 13px; }
    .skh-btn--eq { font-size: 18px; }

    .skh-expr { font-size: 22px; min-height: 28px; }
    .skh-display.is-result .skh-result { font-size: 34px; }
}

@media (max-width: 520px) {
    .skh-wrap {
        padding: 18px 8px;
    }
    .skh-card {
        padding: 16px 12px 12px;
        border-radius: 16px;
    }
    .skh-title {
        font-size: 17px;
        margin-bottom: 10px;
    }
    .skh-display {
        padding: 22px 12px 10px;
        min-height: 92px;
    }
    .skh-expr {
        font-size: 20px;
        min-height: 24px;
    }
    .skh-result {
        font-size: 13px;
    }
    .skh-display.is-result .skh-result {
        font-size: 30px;
    }
    .skh-display.is-result .skh-result.is-error {
        font-size: 16px;
    }
    .skh-buttons { gap: 5px; }
    .skh-btn {
        height: 42px;
        font-size: 14px;
        border-radius: 8px;
    }
    .skh-btn--fn,
    .skh-btn--mem,
    .skh-btn--mode { font-size: 10px; }
    .skh-btn--const { font-size: 13px; }
    .skh-btn--op { font-size: 16px; }
    .skh-btn--action { font-size: 12px; }
    .skh-btn--eq { font-size: 16px; }
    .skh-indicator { font-size: 9px; padding: 2px 5px; }
}

/* =========================================================================
   REDUCED MOTION
   ========================================================================= */

@media (prefers-reduced-motion: reduce) {
    .skh-wrap *,
    .skh-wrap *::before,
    .skh-wrap *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}