"""Matplotlib styling shared by all figures (validated reference palette; static PNG output)."""
import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt

SURFACE = "#fcfcfb"
INK = "#0b0b0b"
INK2 = "#52514e"
MUTED = "#898781"
GRID = "#e1e0d9"
AXIS = "#c3c2b7"
# categorical slots (first three validate for all-pairs use, e.g. scatter)
BLUE, ORANGE, AQUA, YELLOW, MAGENTA, GREEN, VIOLET, RED = (
    "#2a78d6", "#eb6834", "#1baf7a", "#eda100", "#e87ba4", "#008300", "#6250d6", "#e34948")
NEUTRAL = "#898781"
# sequential blue ramp (light -> dark) for ordered series
SEQ_BLUE = ["#9ec5f4", "#6da7ec", "#3987e5", "#256abf", "#184f95", "#0d366b"]
SEQ_ORANGE = ["#f6c3ab", "#f09a75", "#eb6834", "#c24f22", "#8f3915"]


def apply():
    plt.rcParams.update({
        "figure.facecolor": SURFACE, "axes.facecolor": SURFACE, "savefig.facecolor": SURFACE,
        "font.family": "sans-serif", "font.size": 10.5,
        "text.color": INK, "axes.labelcolor": INK2, "axes.titlecolor": INK,
        "xtick.color": MUTED, "ytick.color": MUTED, "xtick.labelcolor": INK2, "ytick.labelcolor": INK2,
        "axes.edgecolor": AXIS, "axes.linewidth": 0.8,
        "axes.grid": True, "grid.color": GRID, "grid.linewidth": 0.8, "grid.linestyle": "-",
        "axes.spines.top": False, "axes.spines.right": False,
        "axes.titlesize": 11.5, "axes.titleweight": "bold", "axes.titlelocation": "left",
        "axes.labelsize": 10.5, "legend.frameon": False, "legend.fontsize": 9.5,
        "lines.linewidth": 2.0, "lines.solid_capstyle": "round", "lines.solid_joinstyle": "round",
        "figure.dpi": 110, "savefig.dpi": 170, "savefig.bbox": "tight",
    })
    return plt